Cancelled NOT - Vodacom keeps-on invoicing

How service are not cancelled (with a reference number) and then month later you owe Vodacom money and have a bad credit rating. On the 20/05/2021 I accompanied my elderly mother to Vodacom Cape Gate to cancel my Father who passed away's cell contract. As the contract was in my mother's name it should have been a quick resolution. On cancellation we were issued with order number *** and assured our cancellation was successful. Month's later we found out it was never done by Vodacom - not only did my mother have to pay R871-59 she was also informed that her credit rating has been affected. She now has a new order number *** and I hope and pray this time it will be resolved