No response to complaint

I am a pensioner and needed a security system for my safety. I contacted Chubb security, and they came to see me, they quoted and Chub stated the first three months there would be no charge which I accepted. Chubb started installing the system which took about three weeks to complete.<br> <br> My three months of no fees were August, September and October, my first instalment of R350.00 was taken off 02 November which I agree and two days later another R350.00 was debited to my account. I have been trying to sort this out as the payment was only to be R350.00. To date no-one from Chubb have bothered to contact me to sort out my billing. How do I get my money back