Bad service from Citi Protection for alarm systems

Kindly note I have signed a contract with Citi Protection for my house Alarm System. All signed documents has been send out to them a technician was send to my place to come and install only to find out a few equipments were Outstanding as well as a battery. Thier technician told me can buy my own battery or buy from them but theirs it's expensive like R700. I suggested to buy my own one and wait for the technician to come back. Citi Protection deducted their first debit order from my account with unfinished work until month four. They never called to update me about their delay. Now I send them an email to request for a credit note for the last four months that they have been deducting my money from my account without any service,they don't respond to my email, but send their technician again to my place this time a different one was sent out. He looked at everything and said few things were done but yes the work is unfinished. He wrote on their job card that no job was done things were left unfinished. I even asked him to take a photo of the job card for me to have the information. After the technician came their manager called me saying they can't give me a credited note, I also can't cancel my contract. Then I told him they should give my money back for the months that I didn't get service which my house was at risk and deduct their first debit order once they start giving me service.