I Face GetYourGuide Refund Not Returned to My Credit Card

I purchased an activity on the GetYourGuide website under reservation number gyg2raa7bq5b, and I made the payment using my Yapı Kredi credit card. The activity was clearly marked as cancelable until the day of the event. I have also attached the payment receipt. I canceled the activity because I decided to choose a different one.

However, I still have not received my refund. When I contacted my bank, they informed me that only one refund attempt was made on June 5, but the transaction was not completed. I sincerely hope that my refund for this canceled activity will be successfully credited back to my card. Yapı Kredi is taking an excessively long time to process this transaction, and I am still waiting. My dispute regarding this charge has not yet been resolved.