Vodacom Incompetence

I used to have a Vodacom contract that I only used occasionally, but I cancelled due to a ********** upgrade on the contract. I tried for weeks to get a recording of the call requesting the contract but no-one ever got back to me. Finally I just reverted the contract to prepaid, paid the outstanding balance and cancelled it. Now, two years after it was cancelled and paid off, I get hounded by debt collection agencies because my account was handed over. I called the Vodacom Legal department and they confirmed that the contract was fully paid up and cancelled and cannot explain why the account was handed over. After weeks of waiting for them to get back to me (and enduring more all-hours-of-the-day calls from MBD and the like) I called them to follow up. Apparently the call was closed because they couldn't confirm why it was handed over. They have now reopened it and told me to give them a few days. This whole situation was caused because of their incompetence, and now I have to endure more abuse from debt collection agencies because of their continued incompetence.