Tracker unauthorised debits

I want to report incident wrg my contract with tracker. I got a call from tracker agent selling additional security product but before I could get further info on additional product they said firstly I need to confirm my personal details. I declined to receive additional product, but nevertheless tracker has gone ahead to debit my account for additional product that I did not authorize. I have on numerous occasions called tracker office to seek to cancel this debit amounts to my bank account. on one occasion my call finally when through after waiting for long and the lady on the other end took my details and undertook to have this debit cancelled. I have followed this matter further by calling tracker but most times the phone is put on automatic music and I have got tired and fed up waiting on automatic music. I want tracker to confirm why they allow customer to be debited without full info disclosure and without my authority. This type of incident will make me consider moving to other services providers