What should I do if I don't pay the property fee and the key to the new house?

It is illegal not to pay property fees and keys. If the owner has paid all the purchase price in accordance with the contract, the developer should fulfill the obligation to deliver the house to the owner. Whether the owner has paid the property fee to the property company cannot be used as a prerequisite for the developer to fulfill the obligation to deliver the house to the owner.

Legal objectivity:

The Supreme People's Court's Interpretation on Several Issues Concerning the Specific Application of Law in the Trial of Property Service Disputes.

Article 6

If the owner refuses to pay the property fee without justifiable reasons or fails to pay the property fee within a reasonable period after being urged in writing, and the property service enterprise requests the owner to pay the property fee, the people's court shall support it. Property service enterprises have provided services in accordance with the contract and relevant regulations, and the people's court will not support the owners' defense on the grounds that they do not enjoy or need to accept relevant property services.