The Ladysmith Ford and Madza dealership, has treat us poorly and I think maybe it's because we are not in the same racial group as them

The Ladysmith Ford and Madza dealership, has treat us poorly and I think maybe it's because we are not in the same racial group as them. My girlfriend bought a second hand car from them last year October 14th 2023 because she was a first buyer and with less knowledge of cars, they sold to her an Opel Astra 2011 model that has no service history and when you look at the service document, nothing is documented. Today we've brought the car back in hope that she could cancel the deal because of their customer service is very poor. We meet one of the managers and he told one of his employees to take the to an electrician and we don't where (at that time I left the his office because I was very angry) after they the car at 08:45 we waited hoping someone will give a feedback to our surprise the manager left for Mosque for prayer and lunch without giving us any feedback. So went to the bank seeking their advice about cancelling the deal, they said it's the dealership who has that power. We are looking for advice what can we do to resolve this matter?