Vodacom - the impossibility of cancelling a contract

I had a Vodacom data package which I tried cancelling way after the expiry of the contract as I did not use it at all. Following extended time holding on various calls to Vodacom, I found an email (***) to which I sent a cancellation instruction on 2 July 2020 to cancel the contract with immediate effect. The debit order kept on going through and in October I furnished my bank with proof of the email instruction and requested that the debit order be stopped.

Since early February I have been inundated with calls from Vodacom threatening legal action on an arrears account. The one lady I spoke to on 24 February, stated that she can see the instruction of 2 July and that the Collection Team must have omitted to change the account to pre-paid after which I was transferred to the Collection department who, after hearing my side just transferred me back to the cancelation department. The next person at the cancelation department alleged that I cannot cancel by email and following a long discussion, agreed to escalate the matter. I have since had 3 further call from Vodacom - non of which are from some form of management who can resolve the issue.

I will NEVER sign a debit order for any form of Vodacom contract again because it seems a physical impossibility to get it cancelled again!!