Why is it impossible to get someone to cancel our account?

On June 26 we returned our equipment and told the "associate: there to cancel our account.  We were moving and the town we were going to doesn't have Xfinity.

It took about an hour for him to accept the equipment because someone had already signed up for sservice at the address and it wouldn't let him accept the equipment, and that he needed a manager to do it, but there was no manager at the store.  Eventual he came out of the office and told us we were all set, we asked for a receipt, but he said he couldn't print one (that should have been a huge red flag for what was to come).

A couple of weeks later we get a bill for July forwarded to our new address.  No big deal I think I'll just call and get it resolved.  I spent about 15 minutes talking to a robot (that kept refering to me as Miss Richard), eventually the robot sent me to a real person.  I explain the situation to her to seemed very polite and friendl and told me we were all set anf now owed nothing.  Unforunatley I didn't get a refernce number of any kind and don't remember her name.

Then yesterday we get another bill with July now past due and for August. Now mind you, someone else is getting service at the address, and we have no cable boxes or modems if we wanted service (the bill even credited us for the equipment).

We try calling again and can not get a real person, so we try a chat.  We were on the chat for over an hour and in the end were told the charges would come off the bill in 12 hours and they would send us an email to confirm. Well its been 18 hours. The charges are still on the account and no email.

We have spent way to much time trying to resolve this issue, why is it so difficult?