CONTRACT CANCELLED AND THEY ARE STILL BILLING ME

Went into the vodacom shop to cancel my contract and was told I have to phone a specific number to have the contract cancelled as they couldn't do it from the shop!! I then phoned the given number and cancelled the contract on my phone which had expired. They have now put through a debit order on my account for R471.21 claiming that this is arrears for my handset? <br> This is THEFT. I have been put through to about 5 different departments all unable to assist because I am no longer on their system.<br>