Complaint Review: VMS ALARMS

This company called and said I won installation of a alarm system. They sent a man here to install it. He didn't ask permission to drill a 4 inch hole in my wall. He didn't tell us we only had 3 days to decide we didn't want it. I called on the 4th day and wanted it removed and was told it was to late they couldn't remove it. So the guy said he would give me a discount price to keep it. When they took it out of my checking account they took the full price so I tried calling them. The 1st time I was told they would check it out and call back. They didn't call back so I called again and again they wouldn't answer the phone. After about a week I did get an answer. They lowered my payment. My 2nd question is can I send it back without being sued for the remainder of the payments? I am worried that if I need the service I won't get it. I was also told the the necklace that came with would work any place. I can't go away more than 20 yds.The thing is a piece of junk.