Cancelled my account, they continued billing me and suspended my service due to non-payment

Cancelled my contract at the end of July, was paid up to date and everything, they continued to bill my account, after a few calls to log a dispute to no avail they suspended my service, I paid the last amount that was sent to me via sms and when I phoned to reinstate my service I was told that I still owed more money, I cancelled my account due to me losing my job and struggling financially, very poor service and had basically no assistance to get the issue sorted