SunExpress Overcharges for Ticket Change – Refund Denied

I purchased a Sun Eco+ package ticket from SunExpress for a flight to Amsterdam, costing 35,943.62₺. As part of the package, I attempted to change my ticket to a Düsseldorf flight priced at 22,128₺.

Instead of refunding me the difference, I was shocked to be told that I had to pay an additional 3,810.34₺! How is it possible that a lower-priced ticket requires me to pay extra instead of receiving a refund? This makes no sense and feels completely unfair.

I demand a proper resolution, either by adjusting the fare correctly or refunding the overcharged amount. SunExpress needs to clarify this pricing issue and honor fair ticket changes.