Product: Checking or savings account

On the day of XX/XX/year>, when i logged into my checkings account to make sure all finances were in order, I noticed XXXX unauthorized transactions from a merchant called XXXX XXXX XXXX  XXXX, with the individual transaction amounts varying in size between {$50.00}, {$100.00}, {$300.00}, and {$1000.00}, the majority being for {$1000.00}, coming to a total of {$17000.00}. I immediately called the Citibank customer service number and and my call was transferred to the dispute department, where i made the fraud claim. I detailed that I have no history with this merchant and upon thoroughly checking my belongs and my home a few days later, proceeded to inform them that the associated debit card, ending in XXXX, was also missing. The last time I had used the associated debit card to make an authorized purchase was the same day I noticed the unauthorized transactions, XX/XX/year>. I purchased food from XXXXXXXX XXXX XXXX XXXX XXXX XXXXXXXX IL XXXX in the amount of {$38.00} and XXXX XXXX XXXX IL XXXX in the amount of {$100.00}. However, I had used XXXXXXXX XXXX through my XXXX to complete these transactions when I was in the restaurants in person, so at this point, I was not aware that my debit card had been lost or stolen. The last time I had physical possession of the debit card ending in XXXX was on the XXXX of XXXX, 2024. Citibank proceeded to immediately freeze the debit card and send out a new one, and after opening the fraud dispute claim, said that their team will be working on investigation the claim, and if they can not resolve it with XXXX business days, then a provisonal credit of {$17000.00} will be credited to my account. On XX/XX/year>, I got an notice in the mail that Citibank has completed their investigation and concluded that the transactions were authorized. I asked them for more information on what documentation they used to reach that claim and whether they contacted the merchant as these authorizations clearly were not authorized. They said can not answer those details on the phone and that I should receive another notice in the mail with those details. Despite the Citibank account manager specialist telling me so, I have received no such documentation in the mail, and when I called back they refused to answer my questions on why they reached this conclusion and the process they used to do so, as well as whether they even contacted the merchant. I am aware that banking institutions expect consumers to contact the merchant directly before reaching out to the bank for a dispute, but since these are unauthorized transactions with a merchant that I have no history with, I have no basis with which to negotiate with the merchant. After several calls and requests to speak to a supervisor, they decided to appeal the claim for me by refiling the dispute and having their case specialists evaluate it again. On XX/XX/year>, i received yet another notice with the same exact information, that my claim was not honored, with no again additional information regarding why. These are fraudulent transactions which total for {$17000.00}, which is an incredibly large sum, and the fact that this money has been compromised for such a long period of time is paying a significant toll on my financial responsibilities. Citibank keeps denying my claims without any comprehensive information as to why, has not even informed me as to whether they spoke to the merchant, or tried to reach out to me for additional information after the initial disputes have been filed. Citibank is not only required by law to provide this information but also provide me with a provisional credit as established by Regulation XXXX as I have been pursuing this case for over 20 days now. Anytime I have gotten in contact with a dispute case manager since the dispute result, they refuse to answer any of my questions and either try to end the conversation or hang up on me entirely. I have called Citibank over XXXX times regarding this issue in the past 20 days.