Very very bad service

I am very disappointed in the service I received from telkom. It is a Sim Only plus router for R139 p/m. On the 9 September 2020, I received my order via Courier it. Today is the 16 September 2020 and still my Sim shows No Service, during this period I did contact telkom on 10213 and 081180, but the Sim is stil on no service. Is it possible to cancel the contract with telkom. Because that is the best option for me.