Inability to process a refund!

Thoroughly and utterly fed up with MTN!!!! I took out a contract at the beginning of May, for a mobile router. After 4 days, they could still not get the SIM card to activate. I spent HOURS in the store, for 4 days. I then told them to cancel it - as I have a right to do, as per the Consumer Protection Act. It is now September and they continue to bill me for the contract, claiming that they went over to a "new system" and it's not able to process refunds and cancellations!!!! I have sent tons of emails, visited the store several more times, screamed and performed - and nothing has been done. I got hold of the area manager, who sympathised (big deal) and said there are hundreds of customers in the same situation. NOT GOOD ENOUGH. I lost a huge chunk of my income due to COVID and now these ******* are helping themselves to my money every month, for a service I never had!!! They owe me about R1000 now. I'm powerless to do anything as my cellphone account is linked to this invoice, so bouncing the debit order will mean my cellphone will be cut off. I've contacted the area manager again. No answer. How long are they going to hide for???????? I WANT MY MONEY BACK!!!! Taking money from someone's bank account for no reason, is tantamount to *****.