Toyota Hilux VEHICLE body cracks

We have been very loyal Toyota customers. It is our third double cab Hilux that we have bought. Very unhappy with our last buy. It is a 2019 model with only 66 000 km on the speedometer. It was bought brand new, unfortunately out of 3 year warrany. The corners of the back of bakkie have begun to make small tears. This is unacceptable as the bakkie is almos brand new. The dealership is not helping and refuses to acknowledge that this is a manufactures weak spot and certainly not everyday wear and tear. We have taken the vehicle for a quotation and the remarks were that they frequently get this problem wit the Toyota Hilux Double Cab bakkies. Dealership refuses to pay for fault.