Installer broke my dashboard

On the 9th April 2021 i got my car ,which is pre owned ,we indentified things on the car that need to be fixed with the dealer ,which was nothing on the interior of the car ,we have pictures with the dealer showing the car was still intact before i took it ,on the 11th of april an installer from car track came to install he worked while i was in the house ,my husband left ,he worked on the left hand side of the car (which he is now denying),after he brought a form without explaining what it is or and said i must sign,which i did ,next day i see damage on my dashboard ,i immediatly loga query to car track ,till today its not sorted,they sent an inspector by the name of president Mokwena who had already taken the story of the installer ,he was telling us that the installer said this and that and called the installer where he was arguing with my husband that he told prior to installing the tracker which is a total lie ,i want to cancel my contract they tell me i need to pay .I want car track to fix my car ,i have pictures showing that the car was still intact.