Account Debited for +-15 months

I was a client of chase tracking for about a year before i cancelled my policy with them because i sold my Nissan Navara late 2016 and got n new Isuzu. I then informed Chase tracking that i have sold my car and will no longer be making use of there services. Today 30 Jan 2018 someone from chase tracking phoned me to inform me that my account is in behind with R339.00 i informed the lady that i have cancelled this tracking service more than a year ago and offered to sent her my purchase agreement that clearly states that my Navara was sold more than a year ago. I then asked her to please stop debiting my account and refund what has been taken she said they they can not an i need to settle my outstanding balance of R339.00 and pay a R200.00 cancellation fee i told her that they can deduct this for the R3000.00 that they have taken over the last couple of months and keep the rest if they don't want to refund it but I'm not paying them another cent but they informed me that this can not be done and i have to pay them, I asked her to transfer me to someone that can assist me as she does not understand me and what im trying to say. She then transferred me to another department and the call dropped after that i have tried call back with no answer only listening to the music playing for 10 min at a time and then the call getting dropped again i have also sent a call back request with no feedback and nothing happening.