I don't have a contract with Vodacom, yet they continued to bill me?

I had a 2GB contract with Vodacom many years ago which expired many years ago, but I never cancelled. In 2017/2018 I changed the debit orders I wished to keep to my new bank in 2017/2018, I called Vodacom to cancel the debit order as I didn't wish to keep it. I'm trying to apply for a home loan and I'm told that I have a Vodacom bill outstanding. I've tried to call Vodacom to understand, however I have had no joy. 1. I'm being sent from pillar to post. The servicing department posted me to the billing department, who posted me to the cancellation department, who posted me to the servicing/account department who on the last call were positng me to another department when the phone cut. 2. The most frustrating thing is that with each transfer the phone keeps cutting because I need to enter an ID number or telephone depending on the department's requirement, and each time I do, the voice recorder tells me that what I have provided is incorrect, even though it's not. And I'm told to call again and the phone just cuts. 3. Vodacom claims not to have record of the request for cancellation and I'm asked to recall which day, more that 12 months ago, I called. How ridiculous is that? 4. The questions I have which haven't been answered are: 4a) What contract do I currently have with Vodacom which has warranted for them to continue to bill my account even though I have requested for them to cancel it? 4b) If I was on a month to month contract as they claimed, who authorized this? W What gave Vodacom the right to continue to bill my account after the first failed debit order (considering that they would have known that the account was closed), because that would have meant that the month to month is now over?. 4c) What is the way forward becuase this matter needs to be resolved ASAP? 4d) Can one person call me that I can liaise with instead of being sent from pillar to post?

This is horrible customer service!