Pay for something you did not get even when you cancel you still pay!!

On the 19 June 2020 i took up 2 MTN sim only data contcontracts via Mondo, and the were delivered after few days. Problem is both sim are not working up to today due to Rica issues(RICA BARRED) despired several calls and sending documents. I tried to cancel the contract a month later because in not receiving the service but i was tild i will have to pay R1300+ incl CANCELLATION fee plus installment for service i did not receive. Im frustated and very much annoyed