False Charges to a Non-existent Account

After a long dispute with Vodacom I had my account closed with a balance of R747 owing to Vodacom. As a result my Vodacom number was discontinued and I had to get a new number. Vodacom then handed me over to collections attorneys for the outstanding amount of R747. However, for last three months they have been sending me statements as though my account was still open and that I had been receiving the previous benefits which meant that the balance grew from R747 to over R1500. When I call Vodacom they tell me they can’t access the account because it’s with the attorneys and when I call the attorneys they tell me they don’t generate the statements and that I should call Vodacom which has become a long back and forth over the last couple of months. Can someone competent please help.