Cyber Sleuth Supreme - not so supreme

We had 3 new tracking devices fitted into our vehicles on the 12th May while the vehicles were still at the dealership. We took delivery of these vehicles between the 14-15th May. On the 16th May we noticed that they were not working correctly. One vehicle wasn't moving at all according to their website and the other 2 were delayed by about 3 hours each. Their reporting system does not work properly giving no information at all at times and the functionality on their website does not give reports for all vehicles even when we select this option. We requested that these units be removed as we were not happy with their unreliability and reporting system as we use these reports to track our technicians which at the moment we cannot do. We have emailed Altech Netstar and spoken to various people telephonically but they are not assisting us. We have a right according to the consumers act to cancel. Seeing as though these units never actually worked properly we don't see why we must pay penalties for cancelling as they did not actually provide the service that we signed up for.