Corendon Airlines Ticket Change Fee Unreasonably High – No Refund Option

I purchased a flight ticket from O Biletten for Corendon Airlines, but I mistakenly selected carry-on baggage only instead of a ticket with checked baggage. When I contacted them to change my ticket to one that included checked baggage, I was told that my 9,497₺ ticket was non-refundable and non-changeable.

Instead of offering a reasonable adjustment fee, they demanded 12,500₺ just for the change! This is completely unacceptable. How can a ticket change cost more than the original flight itself?

I am extremely frustrated and demand a fair resolution. Corendon Airlines and O Biletten must review their unjust pricing policies and provide reasonable change options for their customers!