Not happy with service received from Telematics

I bought a car in November 2016 through Wesbank and was advised that the tracker was already installed . I never made a payment to Telematics because wesbank paid for it . I traded in the vehicle in July 2019. I then got another vehicle and a sales lady from Telematics called me in October 2019 and i took their offer and the tracker was installed in the same month on the new car . I gave them my banking details and they didn't debit my account . They sent me a statement in January stating that my account is overdue and when i checked the statement there were two vehicles not one . I told them that i'm not going to pay for the old car because it was traded in and wesbank paid for it . I told them to cancel the contract and they said i must pay R900.00 which i didn't pay because i refuse to pay for the old car which was paid for by wesbank . Today they sent me an email saying that my account has been handed over to their lawyers , like what the hell . No one has even bothered to call me .