Paying for service I dont have

For the past 5 years i have been charged for an indoor extension. In the past i asked what that was but i was told i had a extension in my place and that i needed it in order to connect to the Internet. This week I found out that i actually don't have a extension, seeing that I also never had 2 phones (i was correctly explained what an indoor extensions REALLY means)i was miss informed what that meant and on top of it all, been paying R14.99 for something I do not have or asked for for the past 5 years! This is RIDICULOUS !!! I asked TO get it removed and the store told me to call in, i called in but never got through to anyone. I want my money back! On top of everything I'm paying for a 4mb line and i don't even get that EVER! This is a *******!