Double debiting off my account

I had an camera and security system installed. The contract said i get 3 months free before paying and started debiting from my account from dec. To top it on the last day of the month they debited R470.50 and on the 1st R480.50. The one debit order i send back and both with dìfferent log numbers. I send my bank statements of proof to *** and she has been harassing me but she has all the proof by her. Pathetic to say the least. Who authorized 2 payments off my account. Will be taking this matter to the ombits man