incompete staff and poor service delivered to you client

I phoned after 20th of this April just query about the debit order which was taken from my account , and i did spoke with Meto Tiyane from account department , and i didn't like the way was talking to me because he was raising his voice to me and i asked him to speak to his boss , and he mention to me that Donald Mahlangu will phone , but even today i have never receive any communication from cartrack personnel. I and i don't like they way they treat their customer because your not doing me a favour at the end of the day as I am paying for this service and i am surprise again on 30th of April my account was debited with an amount of R89 , can someone who is compete explain it to me , because according to Meto he mention to me that they won't debit my account until on may , which my account with debited with that R89 plus remaining amount of device.

below is the email which i have send to clientservice,but still no repond.

Would someone please explain to me why my account was debited with an amount of R236.50 ,I am aware of R 499.90, but according to my understanding is my monthly premium is R89, not R236.50. >> I cannot afford to phone every after debit order to find out what happened to my account, please rectify it or else I will cancel the service with you and take one with your competitors .