Turkish Airlines Changed My Seat Without My Notice

On my September 14th flight from Istanbul to Diyarbakir with Turkish Airlines, the seat I paid for was changed three times without any notification. I spoke with customer service and was assigned a non-equivalent seat. Additionally, I was not refunded the seat fee. Despite informing them of my asthma condition, I was forced to sit in that seat at the airport without any consideration. Instead of refunding my seat fee, they offered me miles, which I did not ask for. If I cannot sit in the seat I purchased and you have the right to change seats, you must refund me. Furthermore, the seat change should be to an equivalent seat, but my seat was changed from 8 to 19. They gave my seat to someone else and claimed it was due to an aircraft change, yet they could have reassigned me to the same seat as I was not seated at the back. I felt completely disregarded, and my refund was not processed. I had a very unpleasant journey, spending 2 hours managing my asthma. Is this how Turkish Airlines treats its passengers? Additionally, my refund was not processed, and I am filing a complaint.