SOS 24/7 extorsionist

I am really shocked at the service I have received from the management team at SOS 24/7 security service for Edenvale area. They are arrogant and unsympathetic towards there customers and they have just showed me that there no 1 goal is just to make money and not worry about there customer being happy. I went with SOS on the recommendation of a friend but I have not even been with them for half a month and I have not had a good experience. Basically I am being charged extra on labour due to them not ordering what was requested on my initial quote and management do not want to meet me half way. There was parts that were ordered wrong and parts that were not ordered at all and now they want to charge me the extra labour to come put it in where as they already charged me labour to install these items in my initial quote which I have already paid. Due to this I have requested to cancel my contract and management are not willing to do it. They say it is not a good enough reason to cancel my contract. They want me to pay my full contract out even though I have only been with them for only 2 weeks. Now I am stuck with an alarm system that is only 3/4 of what I wanted and can't be completed as SOS want to extort more money out of me first. Is there anyone that knows how I can go about canceling this contract without having to pay the full contract out. I can't be part of a business that is only focused on making money and not their customers.