Product: Checking or savings account

On XX/XX/2021 I went into HSBC bank in XXXX XXXX, New York in order to dispute a charge from a merchant called XXXX XXXX. This company had made unauthorized charges on my HSBC debit card in the amount of {$150.00} and {$50.00}. I filed my dispute and was told that I would be given provisional credit. This credit was processed on my account and I had hoped that the matter was resolved. XXXX  XXXX had already told me that I would be refunded my money, however since they had not actually issued the refund and I did not trust that they would, I decided to dispute the charge. This company has yet to issue me a refund even though I have an email from them stating that they would. This company has received many XXXX XXXX XXXX complaints and I suspect they are not a legitimate business. Despite this, HSBC sent me a letter which I received on XX/XX/XXXX, threatening to reverse my provisional credit based on the company 's response to my dispute. HSBC gave me only 3 days to respond to this threat and did not include an email or a direct phone number to their billing dispute department in their letter. I had to call and speak with several people at HSBC before finally obtaining an email address to send my response to. I informed HSBC that I did NOT want the provisional credit removed, that I was still asserting it was an unauthorized transaction and I told them once again the company already admitted wrong-doing and promised me a refund. I even forwarded an email I received from XXXX  XXXX where they had in writing that they intend to refund my money due to their error. Despite this on XX/XX/XXXX, HSBC reversed their provisional credit of {$150.00} based on information that did not prove that I authorized the transaction. This bank decided to side with a fraudulent company as opposed to one of their long-time customers. In addition, I am supposed to receive a certain amount of consumer protection when I use my HSBC debit Mastercard to make purchases. Therefore, I do not know why HSBC is bumbling their handling of my transaction dispute. I feel as if I have to jump through hoops in order for HSBC not to pay a merchant that I said made unauthorized charges against my account. I am supposed to have automatic protection when a merchant uses my account without my expressed permission and authorization. I told HSBC that I never gave XXXX  XXXX permission to charge me an additional {$200.00} and they provided no proof that contradicted my statement. HSBC has been difficult, unhelpful, and unprofessional in their handling of my dispute. I also feel that they are not complying with the written agreement regarding the financial protections that I am supposed to have when using a card with a Mastercard logo. I am not supposed to be held responsible for unauthorized charges against my account, period! If HSBC wants to show me written proof where I signed for or authorized this merchant to charge me {$200.00} in additional fees, then they need to produce that information. An unsigned piece of paper from the company saying they have the right to charge additional fees is insufficient because you can not prove that I agreed to pay those fees!