Turkish Airlines Ticket Purchase Issue and Service Fee Concern

I can say that I have never seen such an arrangement in my life. I am trying to purchase a ticket from THY's website, I get to the payment stage, even enter the 3D Secure code, but the page does not approve and does not redirect to confirm the transaction. When I call the call center, they try to sell me the ₺2700 ticket for ₺3200 under the name of a service fee. Why should I have to pay the salary of the call center employee? For what service are they demanding an extra ₺500 from me? Moreover, the call center representative, Ms. S*****, after trying 3 different banks and 6 different cards, tries to shift the responsibility by saying 'it is probably related to your bank'. I think you should prioritize improving your infrastructure instead of spending on advertisements, if there really is a system issue. The arrangements of the Grand Bazaar merchants pale in comparison to yours.