Sixt Pristina Airport Delayed Refund of €1000 Deposit

I rented a car from Sixt at Pristina Airport in Kosovo from 30.08 to 06.09 and was assured that my €1000 deposit would be refunded within two weeks. However, it's now the third week, and I still haven’t received my deposit. Every day, I’m told, “tomorrow, tomorrow,” but nothing happens. They have also stopped responding to my messages. This delay is unacceptable, and I expect Sixt to process my refund immediately. Please resolve this issue promptly.