Vodacom - Terrible Service

Vodacom issued an Invoice to me for a service that I do not have. I had a Vodacom LTE Contract, which was cancelled by Vodacom due to the fact that could not provide a signal at my address. It was cancelled with no further cost (I have proof of this). Then the next month they issued the invoice of R912 for service that I never had. They used the same account number and mobile number as wasused for the LTE contract. I queried this and the agreed that it was wrong and they said that they will refer it to their legal team. Eventuaally they said I must email the case to refunds. I did get an answer from the Refunds department that they are busy with it but I do not get refunded. I am a pensioner that require every sent to get by monthly. Ria