I want my money back Vodacom

After 20 months of paying for a Home Internet router for R700 per month that is not working and it will not work because of no coverage from where I am staying, Vodacom decided to cancel my contract after I laid a complain. Which I am happy with but still I am requesting for my money back because I was sold a contract that is not working and will not work. Why did Vodacom sell me a contract that they know that it will not work. I was ****** by Vodacom. This is my third requesting asking for my money back. Can I have all my money back that I have for the last 20 month?