Why is it on holidays our substitute mail carriers think it's ok to send a note to the post office (which I am signed up with informed delivery) that he couldn't access our aptmnt complex to cover his tracks for going home x-mas Eve vrs delivering

Unfortunately there are some bad apples, but the majority of mail carriers are not like that. Call to make a complaint, and make sure you get the name of the supervisor that you talk to. If you are able to get a hold of the postmaster, even better.

You will have to ask the postmaster (manager)