Corbeil Appliances

We purchased several appliances for the kitchen in Corbeil appliances store in Mississauga. Upon delivery we did not notice a huge dent in the dishwasher (it was hiding under the shrink wrap). Store manager said there is nothing he can do and we have to install the damaged appliance and live with it because we signed the paper upon delivery. The dishwasher is still sitting in it's original packaging and we are trying to figure out what to do... Several pleadings and explanations lead us nowhere. Not the service one would expect in Canada!