I paid the property fee for buying a second-hand house for two years, but I never got the property service contract, and the owner ignored me. How can I protect my rights and interests?

There are two problems here. First of all, about the contract. It depends on who should be the obligor of the contract delivered to you.

You said yourself that you bought a second-hand house. Then the original landlord will give you the whole set of materials when handing over. If the property contract has been signed before and has not expired. Then the share held by the owner should be in the hands of the original landlord. It is unreasonable for you to ask the property management company to give you another copy. It has no obligation to give it to you. You can't pass the buck.

As for property services, since you are the owner, you should complain if you have any opinions, and feel that it has caused you losses. There is evidence to sue the property company.