Outstanding amount

Good day I had a multi Choice account of which I terminated on the last day of November 2020 because of relocation. My payment date was the 28th of every month normally if I did not make a payment they give me until the 3rd before they disconnect. So today I received a call that my account owes R230 because it was viewed for almost 14 days in December 2020.i don't no how is this possible cause I terminated the account and under normal circumstances they won't even allowed you more that 5 days if not payment is due.i can't and I won't allow multi Choice to take advantage of me.