Multichoice HARRASMENT!!

In April 2019 I asked for my decoder to be reconnected for 2 weeks. They requested a payment and I authorized a debit order. I was asked to use the self help service to activate after they received my payment. Did that. 2 weeks later the decoder was not switched off. I called. Nothing happened. They did not run a debit order against my account and a few days later the service was switched off. Now here is the funny part. Never once did anyone send me a statement, I never used my decoder again. All out of the blue I received a phone call in November 2020 stating that I owe them R480. Hahaha. Really, you wait that long to claim I owe you money. I have had non stop phone calls since then, sometimes up to 6 times a day. (Maybe they are running a bet on who can get me to pay?) Every time I said that they need to go and listen to the phone call that they mention gets recorded, where I state that I would only like the service to run for 2 weeks. Guess what? They cannot find the recording. I also requested an updated statement from every person I spoke to and eventually received one in my junk mail about 3 weeks ago. Since then I have had in excess of 5 phone calls a day. I actually have a job and cannot waist my time on these petty calls anymore. How do I get them to STOP CALLING!!!!