Can I refuse to pay the property fee if the property does not tell me the unit door password?

You can't refuse to pay the property fee

Theoretically, it is reasonable for the property not to tell you the password of the security door. The spread of this password will affect the safety of your house. You can file a claim on this basis, but you can't unilaterally refuse to pay the property fee.

Personally, I think that the password of the security door in your community is lost, which may be caused by the private behavior of property personnel, such as cleaning and security personnel. It is obviously impossible for you to ask the property department to formally tell you the password. If he does tell you, you can sue the community for illegal management, and he will stop talking. You might as well ask the cleaning staff who cleaned your unit, or ask the residents in the same unit directly.