Outstanding Acc Due to non service and agreement

I had an alarm fitted in October 2014. The agreement was that I would get one month free. The alarm continually went off they continually sent out a technician. It was the same technician from Pinetown. Eventually in December 2014 the fitted a new system acknowledging that the system had a fault.. I have not opaid for October November because of a faulty system fitted and December I deem as my free month. Numerous phone calls emails responding to sms's has got me no where. Again yesterday I spoke with a lady Pontso in JHB on *** who promised to phone me back. By around three I called her as she had not called me and she informed me that she had said she would phone me back by close of business. As of this morning still no call my alarm is faulty and they told me yesterday they wont fix it till I pay and also they will hand me over in 7 days. I don't like doing this but I have tried all other avenues .I feel that they are in control because I cant fix my alarm without paying but they don't respond in any way to my queries and I feel I have a ligitamate grievance