Pegasus Airlines Partial Refund Issue: Missing €10,153.54 Refund

On June 6, I purchased a round-trip ticket from Sabiha Gökçen Istanbul to Budapest (PNR: FSTRXL). Due to visa issues, I had to cancel my ticket. I was supposed to receive a refund of ₺10,153.54, but only ₺3,574 has been refunded so far. My bank has stated that no additional amount has been processed for refund. When I contacted Pegasus customer service, they acknowledged the partial refund and created a new application (No: 10756787), but no additional refund has been provided. This is the third time I have called customer service regarding a refund application (previous refund application No: 10727571). I request that the remaining amount of my refund be processed as soon as possible.