Duplication of account

My friend has been a customer of Cell C for some time. A consultant called and said it was time to upgrade her phone which she agreed to. Cell C sent a new phone but my friend, being a pensioner, decided that it was too complicated for her and asked them to pick it up again and send her a simpler phone. The phone was collected and then she got another phone call from a consultant saying she needs to upgrade. She agreed thinking that it was the same matter but before she knew it she had been ******* into opening a new contract. She now has two contracts and after numerous phone calls to the call centre and visits to the shop at Centurion Mall no-one seems able to cancel the second contract. They all promise that it will be done but it never is. She is still receiving calls from Cell C people telling her to upgrade her phone!! This is very frustrating as she is a pensioner and is not able to afford two contracts. Please sort this out as soon as possible.