Cancelled vodacom account ***9 that vodacom refuses to cancel although the owner has emigrated.

My son has been living in the UK for 2 years. Prior to leaving he did everything that was required to cancel his vodacom phone account. The contract was ended and it was apparently running month to month although he requested it be cancelled. In January he received a notification that he was in arrears. He went online and found nothing on his profile. He emailed all the addresses he could find that his account should have been cancelled. I even went into vodacom Clearwater mall, paid the arrears and was assured the account was now cancelled. My son again emailed looking for assurance that the account was now finally cancelled. Today he received another arrears account. He lives in UK not South Africa. They can see he isn't using the account. He has fine through the process of cancelling the account, giving the months notice etc. More than once. I understood that am account ended at the end of contract time but these service providers take advantage my running the account after consumers cancel. This is theft on another level. This account needs to be canceled by vodacom immediately.