Not responding and not cumming bac to me.

I want to stop my contract but I want the system to be a stand alone system. My contract does not say rent or own. Their system shows rent. But when the battery failed I had to pay for a new one. I also paid for stuff that were not installed. After talking to them for about +- 2 months they sent someone to confirm the installation. I have been busy with this problem for +- 4 months. And if I don't call or visit them, they don't response. And each time I have to explain the entire story all over again to the same person. I took all my payments and contract to them to prove to them what is going on, but I still have not received any feedback.