Denied My Right To Cancel

I have tried to cancel Getmore and a monthly contact for a particular number. Cell C denied me my right to cancel. they always tell me that someone from Getmore cancellation department will call me back since last year March 2019. At some point their consultant told me I cant cancel the contract because I was 1 month behind with payment. your service is bad and frustrating. I want all my money from since last year to daye.