My Turkish Airlines Flight Was Completely Canceled Without My Consent

I purchased tickets for my spouse and myself for a THY Agri-Izmir flight (with a layover in Istanbul). I called customer service to push the Istanbul-Izmir leg of the flight by 1-2 hours. The first representative I spoke with said I could change it for a fee of over 500₺ per person. I said I would think about it and call back. When I called again, a different representative answered and told me there were no available seats for the change. I thanked them and hung up. Later, I noticed on the mobile app that our Istanbul-Izmir flight was completely canceled without our consent. After speaking with six different representatives over two hours, I had to pay 3,300₺ to rebook the tickets. The status of our canceled flight is still unclear. THY has caused us significant inconvenience. I am seeking compensation for my losses.