Product: Checking or savings account

On XX/XX/, I filed dispute in the amount of {$840.00} from the merchant XXXX. Citi Bank sent me a letter in the mail asking for additional information a few weeks later, and I responded to their request promptly with all the information they were asking for. I even called their customer service/dispute department letting them know I submitted the requested information. The agent I spoke, acknowledge receipt of the information requested and assured me that they will resolve the dispute in my favor soon. 

Now, onXX/XX/2023, Citi Bank issued credit for the disputed amount to my account. I called their dispute department to confirm, the the credit issued, is permanent and resolves my dispute. The agent confirmed that indeed, the credit is permanent and the dispute was resolved in my favor since they did not receive enough information from the merchant. 

Then this is where Citi Bank began to exhibit their incompetence. Just a few days after received the {$840.00} credit to my account letting me the dispute was resolved in my favor and the confirmation that the credit was permanent, I received an email notification from Citi indicating that they had issued credit for the disputed amount twice to my account and that they were going to debit my account for the additional credit. I called their dispute/customer service back a few days later letting them know, I only received one credit and not two. The agent I spoke to seemed lost and clueless about what was going on. After being placed on hold for several minutes, he returned to the phone letting their no indications of the alert notification I received and that, I should not worry since the dispute is resolve with a full permanent credit issue in my favor. 

After I spoke to them and onXX/XX/2023, they debited my account for {$840.00}. I called them right away and I was told to write in an appeal before I will be issued the credit. I asked why I need to write in an appeal and no one could provide a tangible explanation. I asked to spek to a supervisor. Again after being place XXXX hold for a really long time, I was finally connected to a supervisor. He indicated that they made an error and that he doesn't even understand why my account was debited. He told me he was going to process a refund to my account. 
Since then, I called citi multiple times for my credit. I have been assured multiple times they made an error and that they were going to issue credit. But I have not received any credit. Most times when I call the agent do not seem to a clue of what is going on. 

Now received a letter dated XX/XX/, again letting me know that they have " finally resolved the dispute and that the credit is permanent. WHER IS THE CREDIT?? 

I have called back several time again and again after XX/XX/XXXX when I received this letter ( attached ) and they keep acknowledging that I should have received permanent credit and that they were going to submit a request for the credit to be issued. Up until now, I still do no have the credit. The last agent I spoke to, categorically stated that she doES not understand why I m being tossed around. She promised that she would ensue I receive credit. Here we are on XX/XX/ and I still do not have credit. I'm so frustrated and exhausted. This is by far the worse customer service experiences I have ever received. I just need my money back! 
They've even issued a letter saying the credit is permanent, yet I don't have the credit. This is not rocket science. It's just cross incompetence and citi bank not knowing what they are doing. PLEASE ISSUE CREDIT FOR THE DISPUTED AMOUNT, I SHOULD HAVE RECEIVC LONG TIME AGO TO MY ACCOUNT.