Does anyone know anything about a ferolli combi boiler?

My boiler has never worked properley from the minute it was installed, I have a wireless thermo (not ferolli) which seems to have a mind of its own, I came in the other day to a cold house yet again, no lights were on on the thermo, i had to overide to get it to come on although it was programmed to come on, it comes on when it likes, I'm fed up now, what can i do, the engineer keeps coming out but only re programmes it?????? what is the real problem before i go mad and who do i complain to ?