Price Discrepancy on Mytrip for Istanbul-Bangkok Flight Booking

I purchased a flight ticket from Istanbul to Bangkok through the Mytrip app. Before completing the purchase, the price was ₺23,159.67. However, after paying with my credit card, the amount charged to my account was ₺24,116.82. I ended up paying an extra ₺957.15. This is completely misleading. I demand an immediate refund of the price difference, or the cancellation of my ticket with a full refund. Otherwise, I will file a lawsuit with the Consumer Court.