Gotogate Charges a Rebooking Fee Plus an Extra Price Difference on Top

Hello, on June 13, 2026, I purchased a plane ticket from Istanbul Sabiha Gökçen Airport to Cyprus (Ercan) Airport, departing July 17th and returning July 19th. When I tried to request a refund on June 15, 2026, I was told that a refund couldn't be issued. Even though I didn't accept this, when I tried to change my ticket date, I was told there would be an extra charge of around $36. Even though I still couldn't fully accept this, I agreed to pay it — but then, because I specified that I wanted to move the date to July 17, 2027 (departure) – July 19, 2027 (return), I was told there would be an additional price difference on top of that.
Even though I agreed to pay an outrageous amount like $36, why is there an additional charge on top of it? As if it weren't enough that the ticket price I bought just two days ago is already $38 cheaper than the current price, how does it make sense to also tack on an extra charge? I am requesting an urgent response regarding this matter.