Poor service

Four months ago I got a call from telkom sales agent about their wifi router, I asked her if there is a coverage in where I stay and she said yes there is.when I received the router it wasn't working, I took it to the nearest telkom they told me there is no coverage in where I'm staying and they can't take it I should call the telkom number to cancel the contract which I did, they promised to come and take the router back and promised me to refund me all the money they debited, even today they did not do any of the above, I'm still paying for something I don't use, I even have a case number ***4. I want this problem to be solved, thank you