A CONTRACT YOU CAN'T GET OUT OF

My cellphone contract ended almost a year ago. I was never informed of this until I went into the Vodacom store to inquire about my contract. They told me I would have to cancel my contract by contacting Vodacom Customer Care on my cellphone. I contacted them and requested my contract to be cancelled, after a lengthy process, they said I should receive an email confirming the cancellation. No email was received and yet again it got debited from my account. I went into the store again and contacted Vodacom Customer care for a 2nd time requesting a cancellation while at the store. Yet again, no cancellation confirmation email has been received and again it was debited from my account. For a 3rd time I contacted Vodacom Customer Care and they ensured me that it has been cancelled and that I will receive the email confirming the cancellation. It is now 6 months later and every month it keeps debiting from my account after trying to cancel 3 times.