Rain subscription cancelled but we still billed

Hi Earlier this year we opted for the rain 5g Sim and router. It worked well (30mb/s) for 2 months then speeds started to drop to under 5mb/s despite us paying R700pm. Tried to call their service number but with no luck. I cancelled the service in mid June 2021 and the service was termination within an hour. July came all of sudden they (Rain) demanded I pay for a service I no longer use and of which they terminated within an hour of online cancellation. This is has affected another service subscription (R250 pm data sim) that we can't pay for as they demand full payment of both (R700pm and R250pm) services to switch on the R250 Sim subscription despite the R700pm service cancelled. This is not on as we ve been with rain (250pm subscription) for years and it would be sad to jump ship now.