Sixt Car Rental Serbia Overcharges, Refund Not Processed

Hello there! Just wanted to share that on February 16, 2024, I rented a car from Tesla Airport in Serbia and they charged me a service fee of 235,000,000 RSD on my debit card. Upon returning the car on February 18, 2024, I was informed that my usage fee amounted to 43,000,000 RSD. They assured me that the remaining amount would be refunded to my card within a week. Unfortunately, despite the passage of time, the refund has not yet been credited to my account as of March 30, 2024. Even after contacting Serbia and Germany regions for a month, I haven't received any response. The Serbia region responds on a weekly basis, indicating that they require a slip return image in order to process a refund. I've been regularly contacting my bank, and they consistently inform me that no refunds have been received. I've already provided my account history to the Serbia and Germany regions, but my balance of 55-60 thousand TL has not been refunded to my account yet!