Unit draining battery

We had a Cartrack unit installed January 2025. Before the installation we asked the technician if the unit will drain our vehicles battery, as the previous unit did and we had to replace our battery not even a year after buying. The tech ensured us that they are now using new technology and that the vehicle battery will be safe. 2 Days after the installation I could not start my vehicle as the battery was dead. We immediately called Cartrack , who told us they will book a technician, 2 days later after not hearing anything we also booked a tech online. Received a message to say someone will be in contact. Up until today we have not been contacted and decided to cancel the subscription. The vehicle, if not going to be driven for a day, must be put on charge, otherwise the battery run flat. The moment we cancelled we got calls telling us to pay the penalty fee before a tech will come and remove. Every call received we asked for an invoice. Eventually on a Saturday afternoon a lady sent us an invoice which was paid immediately. The same evening a debit order for the same amount was deducted. Then the struggle started to get someone to understand that Cartrack now owes us money. Their accounts department says we must speak to Client services, Client services doesnt seem to pick up their debit order, only our payment. Never ever go with Cartrack. We now also need to buy another battery..again!!!