Shoppers Drug Mart / return policy

I purchased a box of razor blades which had a clearance price marked on it. When I took it home my husband informed they were not compatable with our handle so I went to return them. The cashier was not sure if they could be returned so called the manager who told me the same thing. I pointed out that nothing on the bill of sale said final sale and there was no such sign by the shelf on which the product was displayed. He just said this is store policy. I said the consumer should be forwarned. I then asked if they carried the compatable handle and the answer was no. So I have a product that cannot be used.