Cancelation of a contract

I canceled a contract in August 2022 and till to-date I still have issues and not yet canceled 😤. Now they say I have to pay for using the services. I have never used their services as I requested for cancelation the same month after getting the router and tried everything for them to come and collect the Router or option to send it back to them. Now they have sent my name to collectors who are busy harassing me for something they have not resolved from their side. MTN please respect your clients and treat them fairly