Bad service

So when I opened my account with Tracker I was told that the billing of the debit order will start that day when they have installed the tracker in my car. So they did that during the course of the month and the agent that was assist me told me that I will only pay the prorata for the month which I have proof of the recording that this is the case. So on the first debit then tracker debited the full amount of the plan I had chosen and I didn't have a problem with that but was amazed why am I billed the full amount. After the debit day has passed tracker started calling me and saying that I owe them for the prorata and I had explained to them that it's not the case. I even asked them to contact the agent that assisted me and also asked for their manager to call me back but as of today no one has gotten back to me, all they care about is their money and nothing else. Every day when they call I ask them to go to their system and check my complaint and come back to me but no one has even bothered and even their manager who I had asked to contact me never even bother. I have no joy with tracker as they don't care about their customer. All I have been getting is bad service with agents who are trained to get what they want from customer and not understanding the full story behind.