The Uzi is a bit of a gas hog especially on full auto.
I've seen a number of gas guns from a varying brands with slight gas leaks new from the box.
Bio is right about Co2 magazines being prone to leaking very easily if the gasket is dry, cracked, missing, or damaged from over tightening.
Gas guns in general are not plug and play, they require varying amounts of regular maintenance and might require you carry spare components that are prone to frequent failure. If you are looking for something to ride hard and put away wet without worrying about maintenance I'd suggest you stick with AEG's.
Most retailers worldwide do not offer any guarantee explicit or implied on airsoft guns but then again some stores/brands do... I would shop around and stick with the retailer that gives the best after sales support... but to claim REPLICA AIRGUNS.ca as a scam is a bit over the top! Vote with your dollar but I wouldn't be so hasty to shit talk a company for a product they did not make.
Follow the link if you want to know more about return policy's and consumer protection in Canada
Should have done a little more research...