issue with cancelling my account

I had been trying for almost 2 months to transfer my account to a new account holder residing in the same location when I moved out. Eventually we just decided to cancel the account and have my former roommate open a new one. Three days ago I was told the account would be closed by end of day and the final bill would be payable when it populated to the account by end of day. Thus far my app still says the account is active and the remaining balance (note: the regular monthly payment) is due on the 6th (the monthly due date. I want to be sure there will not be late fees associated with this if the correct final bill is not posted by then. 

If this question cannot be answered directly through here, can someone please give me the customer service phone call hours, so I can see if I'm able to call when I leave work today? 

Thank you