Sixt Car Rental Deposit Refund Delay

I rented a BMW from Podgorica Airport in Montenegro on February 13th, and it's been 50 days since then, but I still haven't received the refund of 1200 Euros for the deposit in my account. In addition, the deposit of 800 Euros for a Jaguar rented on February 20th has not been paid, even though both cars were returned without any problems. At first, they pointed fingers at my debit card, promising to fix the issue within a month. However, when I followed up via email after 50 days, I received the response, "No problem, we have already released your funds. It is now solely your bank's responsibility." After reaching out to my bank, I found out that they had sent me an email requesting my information because of "some incorrect transactions." Even though I provided all the necessary information and received assurances that the process was finished, they decided to use delaying tactics. It appears that renting a car from Sixt Rent a Car can be quite a financial inconvenience. After conducting some research, I discovered that there are numerous individuals who have experienced similar effects. I would strongly advise against renting from Sixt Rent a Car, whether it's for domestic or international purposes.