Why did you sign if you were not satisfied with the heating system?
We signed because we were satisfied with the rest, and we mentioned at the time of signing that we did not want this heating system.
The company has already worked with the heating installer we want now. And if they do not provide us with what we would like, we will have to take action ourselves.
Of course also interesting: What kind of heating system are you supposed to get and what do you actually want? That’s definitely a topic for lively debate :P