Unfair charges

I phoned for a new contract with Multichoice in January 2020. The next day I heard that the business was closing and I’d be unemployed. I immediately phoned Multichoice and they assured me everything would be cancelled as I haven’t received a decoder, and nothing had been connected. A few months later they started calling about an outstanding amount of around R3000. Every time I explained what had happened, they apparently understood as it was on the system. They promised to ‘escalate the misunderstanding’ to accounts. That never happened as I’ve now been handed over to a credit company. I did call customer care again, but the operator was so rude telling me that he’d pay the ‘small change’ on my behalf. I’ve had no luck speaking to a manager or anyone in charge.