OnAir tv

In 2022 I had a decoder installed by BCR electronics, but it turned out to be OnAir tv who did the job. The agreement was for R199 per month for 24 months. They deducted the amount twice monthly and all efforts to contact them were futile. After 24 payments, I stopped the debit order and that is when the problems started. They insisted that the second debit order was for something else that I never agreed to. After long arguments, they admitted that I never gave consent and payed back only 3 months premies. I still payed more than the 24 months premiums. I spent hours on the phone with them to no avail, so I started to ignore them. In September 2024, they started deducting R105 per month. I cannot stop the debit order, since they use a different ref no every month. How do I get rid of them. I really wish I never had to deal with a company like that.