Vodacom debiting nightmare starts again

My last contract account with Vodacom has run its course. I called Vodacom and informed them I am not renewing the contract. Vodacom duly converted the contract to pre-paid and everything was confirmed by SMS. A month later Vodacom debited my cheque account. I called the bank and returned the debit order which cost me R75. Today their legal department called me asking for what they deem as an arrear payment. On top of that my credit report shows I am now 1 month in arrears. How is this possible people ??????

Now I totally knew this was going to happen because my previous contract I did not renew they continued billing my account for 2 years afterwards. I had major issues getting them to stop debiting my account. And true to expectations they are doing the same thing again !! I am so never ever going to take out a Vodacom contract ever again.