Refusal to cancel services

After several attempts off cancelling the subscription of the service the services was not cancelled, firstly several emails was send to cancel the subscription several phone calls was made to them, and every time they have an excuse to cancel, firstly apparently there was a sim swop out standing and they do not want to cancel, now after 4 weeks of cancelling they have the audacity to call and say there is an outstanding amount and they cannot cancel the service due to the outstanding balance. The services was cancelled a month in advance before subscription was due and still nothing was done. And they said no contract it will be on a month to month base. This is all lies. Still no cancellation on service, they just want money even though the service was not used from 01 July 2023