You said "YOU" recently replaced the thermocouple on my boiler (it goes out every year). Did you have this done or did you do this? I'm not a HVAC guy but, I don't think it should have to be changed that often.
I recomend you call a different company ASAP and get this fixed.
We have a bunch of people on this site that can help you, I'm sure they chime in soon!