No customer service once you signed a contract

I had several issues with my Chubb Alarm service, Ive been corresponding with Chubb since 4 Dec 2014, spoke to several people, wrote a couple of emails and even logged complaints on their website. I spoke to 10 different people who all promised to get back to me and attend to my issues. No response, I'm not sure what to do because their systems don't allow you to speak to someone in charge, they block you at the call centre and as a result no progress was made