Moving nightmare

I submitted the change of address order,4 weeks before the moving time,once I moved and tried to do the self install, the app said my service was cancelled, and a massive $566 charged marked as overdue showed up on my account out of nowhere,all my bills had been paid on time,after 5+ hours of going around in circles with 8 different agents that kept disconnecting one of them managed to get my service back but instead of moving my address they just created a new account,the old one still has the $566 charge, I asked repeatedly if that would get removed but all I got is " you don't have to pay anything today" which doesn't answer the question, somehow if it wasn't bad enough they managed to mess with my mobile service which I also get through Xfinity, a choice I now deeply regret, these agents were more focused on selling me some random Verizon phone and iPad than fixing the problem, which is still there, I'm not sure if my phone service is going to get disconnected at random since it doesn't appear on either account