Moved Service, new account number, old account still being billed

I moved from an apartment into a new house in the middle of December and set up the move through Xfinity. When I received my bill for January, I realized that I was being charged for both my new address and a balance transfer for my previous account address as well. I have been unable to unlink my previous address from my account, and anytime I try to modify the services for the previous address, it says I need to contact the account owner because I do not have permission to modify services, even though I am the only user profile on the account. My internet and Flex are working great at my new house, but I definitely don't want to be paying for a service at my apartment that I am clearly not using.