No service - paying every monthy for nothing!!

I signed up with ADT Security services in early Sep 2015 for the security alarm system to be reactivated. Johnny Maries came to my house to assess and give me a quote. During the assessment, he told me that my backdoor sensor was mul****ioning and the battery was dead. He advised me to replace the battery which I did. He then drew me a contract for a monthly service of R399.00 and a labour charge of R769.42 to replace the backdoor sensor and to reset the alarm and a pro rata monthly service fee. He told me that labour will only be done once the R769.42 was paid. At that time, ADT was having a special of two months free service for new sign-ups. He promised me that I will also get two months free service and will only pay the monthly fee by end on November 2015. He gave me his business card and told me to call him if ever I need assistance or have a problem., he specifically told me not to call the ADT call centre because I may not get help quickly. On 18 Sep 2015, ADT then debited R769.42 from my account. I waited a few days for an ADT technician then called Johnny on 30 Sep several times but to no avail. I sent SMS's, no response. An ADT official came once and no technician.