Help please I have a level 51 kinda battle mage I have done almost every..

Ah, this is one of the buggiest quests in the game, thus it can be really disappointing.

Read this step-by-step and see if it helps.

Speak with Ahdarji
Speak to any beggar in Leyawiin and you find out that Ahdarji lives on the west side of town, goes to the Three Sisters Inn in the evenings, and eats her midday meals at Five Claws Lodge. Find her at one of those locations, and speak to her.

Ahdarji tells you that an Argonian named Amusei (remember him?) stole the ring. She wants you to kill him and get her ring back. Of course, you can't kill him, so she says to at least make him suffer.

Question Amusei

Talk to a beggar to find out where Amusei is. Pay one of them and you learn that he was arrested for trying to swindle Alessia Caro, the Countess of Leyawiin. You also find out that the guards accept bribes to allow people to visit prisoners. Head to the castle dungeon and talk to the jailor. He tells you that "dirty lizards" aren't allowed to have visitors as per the Countess' orders; however, 20 gold quickly changes his tune. Picking the lock to the dungeon is just as simple, though the lock may be level-dependent (average at level 5). If you don't even want to do that pickpocket the guard and steal his dungeon key. Go downstairs, and ask Amusei where the ring is. He questions why he should tell you. Bribe him with a lockpick, and he reveals that the ring didn't originally belong to Ahdarji, but rather to the Countess. After stealing it from Ahdarji, he tried to ransom it back to her and was arrested. The ring is now in the hands of the Countess.

Steal the Ring

If you talk to Ahdarji about the ring she says she'll make better use of the ring and will pay double for you to steal it back for her. If you talk to a beggar, he or she will tell you to talk to Hlidara Mothril, the Countess' handmaiden, who eats dinner in the castle at 8:00pm. The beggar will also tell you about 'other' secrets in the castle; a torture chamber specifically for Argonians. Oddly enough, you can get the tip about Hlidara Mothril from the Count himself, although he mentions nothing of the torture chamber. You can ask the Countess about the ring too, and she doesn't seem to get suspicious. Speak to Hlidara Mothril, who tells you the Countess' schedule and that she wears the ring at all times except for baths and while she's sleeping, when it's left in a jewelry box. With high enough disposition, she tells you about a secret passage from the torture room to the Countess' private quarters. The Countess sleeps at 11:00pm and her jewelry box is to the right of her bed on the dresser.

Wait until about 1:00am and head to the Castle Leyawiin Basement to find a lever hidden in an open barrel. Pull the lever and the wall will open up, revealing a passage to the secret torture room (there's another lever you'll have to pull hidden in the secret passage revealed by the first lever). Pick the leveled lock on the next door, sneak left past the patrolling guard (using detect life or invisibility helps to avoid him and his route), and pick the easy lock on the private chambers door. Once inside the countess' room, pick the average lock on the jewelry box or pickpocket the key from the Countess, grab the ring, and go out the way you came in. Beware, the guard is still patrolling.If you get caught by him you won't lose the ring.

Reward

Return to Ahdarji, and give her the ring for a 200 gold reward for your efforts (if you don't tell her Amusei tried to sell the ring, she only gives 100 gold). Finally, return to S'Kriiva for a 200 gold reward, rank advancement to Prowler, and your next mission. These are the known bugs found in the quest. Although it sounds to me like you've ran into an unknown one:

1. Hlidara doesn't always seem inclined to say anything about the secret passage or torture chamber, even with an 85 disposition. 2. The dialog sequence can be mixed up enough so that it no longer makes much sense at all. When talking with Amusei in his prison cell, he asks for a lockpick. If you leave to go find one, you may speak to NPCs about the "Recovered Caro family ring," even though you have not finished the conversation with Amusei and found out that the ring belonged to the Caro family. When returning to Amusei to give him the lockpick, you may no longer have the option to give it to him and hear what he has to say. 3. Hlidara Mothril can be killed by the time you begin to pursue this quest. The good news is that her body has keys to the castle, and the Countess will give you enough of a hint to know that she does not wear the ring when she is sleeping. That's really all you will need to complete the quest, but you will miss out on hearing about the torture chamber and secret passage. You could resurrect Hlidara Mothril with the console command player.placeatme 00034E8D if you really want to hear the full story. 4. The Countess' jewelry box can contain two identical copies of the quest ring. Immediately after you pick up the first ring, you will get a quest advancement popup telling you to deliver it to Ahdarji. As for the second ring, you must leave it behind. If you pick up both rings, Ahdarji's dialogue options will no longer include the "I found it, here you go" option, and you will be unable to complete the quest. This means no more Thieves' Guild missions. Also, both rings are quest items that cannot be dropped or sold, so you'd be stuck with them forever. There is a workaround for this on the PC version, use the console command player.removeitem 00035E95 1 twice until the counter says 0.00, then player.additem 00035E95 1 to fix the problem. On XBOX 360, if you accidentally collect both rings and cannot complete your quest, you can murder a NPC in the castle where you collected the rings and a pop up will inform you that you must pay a blood price. Pay your blood price, and you will finish the quest and be able to complete the other quests. 5. This quest cannot be completed while you have Sanguine as a current quest; however, even after completing Sanguine, the Countess may permanently sit down at the dining room table instead of retiring to her bedroom like she should. If this happens, PC users can use the console command player.additem 00035E95 1 to add the ring to your inventory and complete the quest. For 360 users, you should punch her in the face. You will have to pay about 40gp for the assault, it will get her to get out of the chair and go about her normal routine. 6a. You might end up with zero rings in the jewelery box, or at least not the ring that you are looking for. This can happen if you talk to the maid and then a guard and don't talk to Ahdarji before opening the box. It also happens if you first talk to Hlidara Mothril to find out about the Countess taking off the ring at night, and then after that talk to Count Marius Caro who tells you to talk to Hlidara Mothril. It also seems to happen in other circumstances. If this happens, PC users can use the console command player.additem 00035E95 1 to add the ring to your inventory and complete the quest.

6b. A possible bug fix: If you don't find the ring in the box, just head outside the castle and wait for a couple of days or more, then go back in and the ring may appear in the jewelry box. You may need to try waiting multiple times, but it has been confirmed that this fix does eventually work. Another possible fix is to kill someone who belongs in the quest like the countess' bodyguard. You will get a journal update that you have to pay the bloodprice. Pay the price and you will automatically complete the quest, even if you had no rings, this also works with two rings. However, this fix may not work for all players. There have been reports that the the option to pay the bloodprice may not show up in conversations with S'Krivva even after killing, for example, the countess' bodyguard. This bug is confirmed to exist in the Xbox 360 version of the game, but appears to be a rare occurrence. 6c. Alternatively, you can simply reload the game and toggle to a different active quest. The ring should reappear in the jewelry box. 7. A bug could make it impossible to continue the Thieves Guild quest line. If you ask about contracts from S'Krivva, and then decline to accept the contract at that time, it may become impossible to resume this quest. It is recommended that you not ask S'Krivva about the assignment until you are ready to accept it. If this does occur, PC users can correct it by entering the console command setstage TG04Mistake 10. This will update the quest, directing you to see Ahdarji. 8. Occasionally, the ring will not be removed from your inventory at the completion of the quest. As it is marked as a quest item, it cannot be dropped or sold. On the PC, it is possible to use the Console to remove the ring: type player.removeitem 00035E95. If this doesn't help, then you may not be able to continue in the Thieves Guild. Just keep trying and prey for a patch. ;)