CELL C - HOW CAN I CANCEL A CONTRACT THAT DOESNT WORK?

My parents who are in their late 60's acquired a router with an LTE-A contract from Cell C so that they could use WhatsApp and save a bit of money, as well as allow others to monitor the cameras so that we can make sure they safe.

The system has been offline for almost 2 months now. CellC can not assist as they seem to either be insufficiently trained or too busy striking and CellC are not bothered to assist their clients.

We have taken the Router and Sim Card in of which both were replaced. The system still does not work. I then tested a Pay-as-u-go Sim from CellC and suprisingly its working.

My father who is not technically minded has been to CellC many times to try resolve. Ge eventually called me whole at the Shop and I explained to the lady that it used to work and now it's as if she was trying to inform us that we bought something where the coverage is not offered. LIES.

Now my parents have paid 2 months on the contract and had ZERO service from CellC.

Can we legally opt out and demand a refund without any recurrences or problems in the future? Surely there must be some law to protect the consumer?

I would rather get a service provider that cared about their clients.

Can someone please advise me.