Vodacom's horrific services

I had a contract with Vodacom, which was paid off in January 2019. This week I receive a call from debt collectors stating that Vodacom has handed me over because my account is in arrears. I called Vodacom and they failed to help. I called the legal department and they also failed to help. I call the debt collectors and instead of them helping me, they "advise" that I make payment. No payment history sent, no invoice sent, no statement sent nothing. This is frustrating because there was never any communication from Vodacom to say that I owe them. This is ridiculous I must say. How do they keep quiet for 9 months and only now they decide to hand me over? I confirmed with the consultant when I called to cancel that the last debit order will go through on the 2nd of January, but now all of a sudden they are failing to get those records. This is unprofessional and annoying. I am sick of Vodacom and their incompetence!!!!