I just want to cancel the contract of the extenders.

I requested extenders to use with my WiFi. It was delivered to my house but I don't know how to install them. I put in a query for help with it and the guy wanted to help me over the phone. I couldn't do what he told me to do. I want the contract terminated as I'm paying R 115.93 for it for 24 months and I can't use it yet. I also think I can get cheaper extenders which I don't have to pay for for 24 months. I have an account number but when I phone them they can't find me on their system. I'll gladly pack the extenders and courier it back. My phone number is :***. That's how they found my name on the system.