Recently I was flying from XXXXXX to an Eastern European country. We flew over several countries at FL340. When we were handed to XXXX Radar (European Union) they informed us that our Mode A and C were not transmitting. Everything in our aircraft appeared to operate correctly. We tried to troubleshoot, were instructed to hold over a VOR at altitude. Within five minutes of being instructed to hold, we were told to land at an airfield below us. We did not have a diplomatic landing clearance, and when we asked for a lower altitude or simply to provide position reports, ATC said "no- land". We went through the pain of digging out airfield info, descending from FL340 to an unfamiliar airport in our DC-9-32 all while dealing with a pushy controller who could clearly see us on radar. In hindsight, I should have been less compliant, or at least controlled the rate at which things occurred.

Has this ever happened to anyone? What would the ramifications have been if I had simply refused to land and continued along my FP route while providing position reports? I know the answer in CONUS, but in Europe things are a little grey since ATC really isn't communicating with an embassy.

We landed, purchased their fuel and services, departed with no maintenance performed and amazingly enough, they had no issues with our transponder. Any informed comments would be helpful.