New Construction

I am attempting to get service transferred to our new construction home. We are closing tomorrow and, to date, I have been unable to get a straight answer from anyone.  When i spoke with an in-store customer service rep he indicated the new address was not registered with USPS so a new service ticket could not be set up.  He noted that service should not be a problem as Xfinity is being provided to virtually all the homes in the neighborhood.  Today I followed up and was told that the construction department said our new construction was not in the service footprint and it would cost us $500,000 to have 1200' of line run to the house.  The neighbor 30' away has Xfinity so that makes no sense. Please tell me what we have to do to get a straight answer and service established.