Turkish Airlines Ticket Rescheduling Fee Issue

We wanted to reschedule our international flight due to our friends' visa problems. Before proceeding, we consulted with a customer representative to get information about the penalty fees. We were informed that there would be a deduction of $70 + $15 (tax and processing) per flight. For two people, round trip, the total penalty would be $340. I confirmed this amount with the representative, and we rescheduled the ticket. However, when my friend tried to reschedule their ticket, a higher penalty fee was quoted. I spoke with another customer representative and realized I had been given incorrect information. I filed a complaint, and that evening, they called me back, saying they had listened to the call recordings and found me to be correct. They assured me that I could use my ticket based on the information provided. I sent an email for new ticketing. While my ticket was worth $1000, after the $340 penalty, I expected to have $660 (approximately 20,000₺) in usage rights, but only a 9,000₺ discount was applied to my new ticket. The customer representative kept pushing me to buy the ticket quickly, saying the price was increasing, and tried to close the complaint file. They couldn't explain the 10,000₺ discrepancy, constantly saying the system automatically gives the amount and there's nothing they can do, citing tax deductions. Additionally, they tried to make me feel guilty by saying the representative who gave me incorrect information would be held responsible. A reputable company like THY shouldn't put its representatives or passengers in such a situation. I am waiting for the result of my new complaint; I don't know when they will respond, and the price of my new ticket is increasing. If the outcome is the same, I will apply to Consumer Rights.