VODACOM - HANDED OVER WITHOUT MY KNOWLEDGE

I am very disappointed in Vodacom, I have been a Loyal Customer for a lot of years and when my Contract was coming to an end Feb 2019 I decided to cancel it. Everything was fine I phoned Vodacom notifying them and sent a email that said once my contract finished I would not like to renew it. Then 6 months later I start getting daily phone calls up to 5 a day from a Legal Firm notifying me that I was handed over and owe Vodacom money!!! The last Statement I received from Vodacom showed that they owed me money?? When I went to the Vodacom Branch to find out what is going on I was told that there was an amount owing a debit order that did not go off. Without any communication from Vodacom for 6 months they just handed me over just like that making my Name bad. I was told they did try phone and sent messages.... how do you try phone and send message on a number that does not exist anymore????????? So basically I was handed over without my knowledge that I owe money and now that I have paid Vodacom and my acc is settled, I still owe the Legal Fees!!!!! Very unfair and very upsetting, I will never again have a contract with Vodacom if this is how they treat a customer after many years of loyalty.