That brings back memories! My very first post on PPRuNe was about this. I'd recently heard a C-5 crew being chewed out by Nicosia for flying in their airspace with only an Ercan clearance. So got them to come up on UHF, explained the problem with the squabbling locals and advised them to explain that they'd been told by Ankara to work Ercan, not Nicosia. Which they did - and the Nicosia controller calemd down a lot!
Dan - we were strictly forbidden to talk to Ercan! Despite asking Arsecoat Ops to sort out an acceptable protocol, they never did. Ercan does not have any internationally-recognised airpsace apart from their ATZ in Turkish-occupied Cyprus. But they are always very nice to anyone who does talk to them as it helps them to legitimise their continued occupation of northern Cyprus.
Coming towards Turkey from the south-west, I used to work Nicosia, then call Ankara 5 min before the FIR boundary. If they told me to recall on a different frequency which subsequently turned out to be Ercan, I just ignored them and called Ankara again at the boundary on the correct frequency with a full position report.
Going south-west, I just called Nicosia just before the boundary for onward squawk and clearance (and, if possible, a 'direct'). Then when told by Ankara to call Ercan, just told them precisely at the boundary that I would be changing to Nicosia with whatever squawk Nicosia had allocated..... Fun listening to the subsequent reaction from Ankara!
When will this stupid bickering end?