Vodacom is useless and *********

I received an email from vodacom stating that I can cancel my home router contract without any cost to me due to their usage policy changing. The router was collected on the 21st of February and after numerous phone calls, it was finally cancelled yesterday on the 16th of March. Now I have a payment due end of March for the FULL MONTHLY AMOUNT even though I did not have the product from the 21st of February and I was charged and paid the full monthly fee end of February. The consultant I spoke with does not have an answer for me other than he is sorry I'm going to be charged. THIS IS THE SECOND TIME I'VE HAD ISSUES WITH CANCELLING VODACOM CONTRACTS! Previously they debited my account for three months after I cancelled my contract and every time I phoned they assured me it was cancelled and then the following month they just take the debit order again. I can see this following the same path. HOW CAN YOU CHARGE ME FOR SOMETHING I DIDN'T HAVE FOR MORE THAN A MONTH!!! Someone better phone me to sort this out and cancel my debit order before the end of March!!!!!!