Lowe's

I bought a role of "Waterproof" tape. It DID NOT do as the product advertised. I tried to return it, and the manager stated "That's funny. It worked for me" He then stated"I can exchange it for another one" Why would I want another one? Then he stated, "I'll do it this once, but never again!" I advised him that he wouldn't have to do it again, because my next purchase would be at Home Depot. He did all of this in front of a line of other customers. I advised him that I am a Veteran, and I was shocked he was treating me like this. I felt like a liar and a thief.