I want my refund back because of poor customer service

Hi I have a complaint about vuma Wi-Fi, I had a very bad experience with them paying for a service that was never provided to me. They came to install the wifi but from the day of installation it never worked, gave error message of connected with no internet excess ever since then I came to a point where I gave up on contacting them sending emails etc. But the only thing is my money to be refunded

etc. But I want my money refunded