I need the wisdom of this group.

I have a MileagePlus award reservation IST-(TK)-VIE-(OS)-PRG-(TP)-LIS. 12500 mile award, 23-hour connections in VIE and PRG.

Looking at my reservations online I notice that the IST-VIE segment simply disappeared. No communication from UA about it, I simply happened to notice. I called UA, and they went "hmmm". They claim that TK canceled the segment. They called TK and were having language barriers communicating. UA can't reinstate the segment because there are no more award seats on that day IST-VIE. They suggest I call back tomorrow daytime, when the TK US desk is open and they may communicate with TK.

I checked my original TK flight. It still exists, same flight number, same schedule, and still available for sale. Just no reward seats available on it.

Has anyone here had something like this happen? What recommendation can you provide to reinstate the itinerary? Can TK be forced to reopen award inventory? Or am I hosed? Help!