Irregular debit

The devices on my vehicles are faulty and have been problematic since installation. The send inaccurate accident alerts, they do not show accurate locations and km’s. After being given the run around for a maintenance check to be rendered a technician finally came, he also had to spend the whole day here since morning because the system was down and the trackers being fixed could not be activated. The maintenance is all within my 12 months warranty and I was told I would not be charged as a result. However, this is not the case because they keep debiting from my account outside of the debit order mandate and approved amount. After being sent from one department to the next, the customer service agent tells me that indeed I should not have been charged as the maintenance falls within my warranty period and that they will escalate the matter and I will be contacted on the next steps of the investigation into the charge and if nothing is amiss a credit will be granted. I am so angry because I have still not received a call from them and they keep debiting and yet the debit order day has still not arrived. I find them to be unreliable and unreachable. I have no faith in their services and would recommend their competitors.