Pegasus Airlines Failed to Cancel and Refund My Ticket

I called Pegasus customer service the day before my flight on October 14, 2023, to try to cancel my return ticket from Düsseldorf to Kayseri (Z3F62A). The system was broken, though, and I was told to call back in two hours. There were more than 10 calls, each one about two hours apart, until my flight time. During the second call, they promised to give me back 1471 TL, even if the flight went through. While I was waiting for my flight, I called Pegasus's customer service several times and bought extra minutes each time. This took about 200 minutes. When I got back to Turkey, I made about 10 more calls. On each one, I was told about a system problem and an application (09349944) was made. They said they would get in touch with me by mail about the payment. I agreed because I was tired from waiting on the phone for 500 minutes. Now comes the disappointing ending. I thought I would get cash back, but instead I got an email offering a refund of 864.25 TL, which would cover only the ticket tax fee, and asking for my bank information. I don't understand this. Why didn't Pegasus cancel my ticket the first time, even though I called them several times? My refund went from 1471 TL to 864 TL. Do I have more money than Pegasus? It is both annoying and disappointing. Our flight from Kayseri to Düsseldorf was also six hours and twenty-three minutes late, which made the whole experience even worse. My simple request to Pegasus is that they give me a real, full refund for the ticket instead of using a canned response. I feel bad about the choice I made after going through this whole thing.