I WANT MY REFUND URGENTLY!

I was paying for router that has no access to internet i would pay full R625, your technicians failed to assist me resolve the issue i requested for immediate cancelation and they sent a courier to pick up the router which they did,they promised to refund me my money now when I call nobody pick up my calls they don't answer my emails.. They keep on promising me that their billing department will call me as soon as possible but no response from them. I just want my refund so i can pay for the network that works.