Extra payment deducted with no cxld explanation

Good day, my car was recently sold and I contacted tracker for options as to a new device on my other car and all options were given and explained and from there made my choice. Been a tracker client for a long time and bad experience and service with matrix on my other car I stayed with the company I trusted. Once the new details were done I was explained that my new system cost and the cancellation amount and budgeted around that. Now when the money was taken from my account I discovered a rather large amount taken and when I called they said it was due to the 30 day cancellation period to which I said it was not explained to me and therefore knew nothing about it. I explained to the lady on the phone that should I have been made aware of this I would have had the money available. I feel this is unfair and should be made aware of this extra charge as now I had two transactions fail on my account due to this and were not paid plus occurred double failed fees from my bank. I need this to resolved as soon as possible as it is urgent as I spoke to agent already and no one has got back to me as yet. Quite disappointing as I recommend tracker to everyone I know due to great service.