johhenrik, thank you for your replies.

I just don't understand the management of this airline.

They spend millions on advertising trying to win clients. Throwing Gold Cards at everyone that sends in a photoshoped status card of another frequent flyer program, yet they don't care to provide a consistent (basic) customer service to its most frequent fliers. Retraining those clueless service agents at the airlines home base, Istanbul, also doesn't seem to be a very important point on the agenda.

Needless to say, I haven't heard back from them.