Trendyol Claims Refund Sent to My Blocked Akbank Account but No Money Received

Trendyol claims to have deposited the money into my blocked bank account. I had purchased a water heater but submitted a return request for the product. I was informed that the product was returned and that the refund was sent to my Akbank account. However, my Akbank account was blocked and later closed. Throughout this process, I went to the bank three times and contacted them 5-6 times. When I spoke with Trendyol, they said the money was deposited into the bank. They initially stated that they would request a new IBAN if the money didn’t go through, but then said it had been deposited, so there was no need for a new IBAN. Just today, I went to the bank again and mentioned the deposit, but the bank said there was no such transaction. I’ve been trying to get my money back for 20 days now, and they keep stalling me, telling me to wait 10 more days each time.