Canadian Tire

I bought a headlight bulb for ny car from store # 427 on June 18th. A sales person helped me finding out the correct bulb for the model of my car with the help of his computer. Once i try to install, I relaized that it's not the correct bulb he provided.
With confidence and experience of shopping with CT for a long time, I wanted to return that incorrect one. Out of my surprise the manager GREG clearly mentioned that it is non-returnable as you open the pack. I tried to make him understand but he was unmoved to his decision. I ws denied to even exchange the product for the right one. Am I at fault? I believe I am not. I would like to return my money back as I am not at fault. BTW I spoke in another CT store, and they were happy to return it, but i woud like to return my product to the store where i bought it from.
Thanks
Ray Ahmed