Mr Price account not closed

On July 25, 2018, I went to Mr Price, Canal Walk to close my account. I payed the account balance, filled in a form and the guy who assisted cut my card up as well. However to my surprise I received an email with a new statement and an insurance balance to pay for the month as it turns out the forms were never sent through for cancellation. Now my concern is more about the fact that I'm leaving the country for a year hence closing the account. So if I was not here to pay the balance what would then happen, would I then be blacklisted for not paying an account which was supposed to be closed? This is truly a matter of concern as now I need to not only pay the balance but also call back and forth making sure that it's closed when this is not my job!