Do I have to pay heating and property fees if I don't take the key to the new house?

Didn't take the key? Did you confiscate the building, didn't sign the building opinion, didn't sign the key receipt and so on?

If you don't (you confiscated the building due to housing quality problems when the developer handed over the house), you don't have to pay these two fees, because you confiscated the building, which means that the house is still in the hands of the developer, so naturally you don't have to pay.

If you sign the bid-winning notice and the key receipt, you have to pay the relevant fees, because as long as you sign it, legally speaking, you have taken over your property from the developer.