Return policy

So I bought a drill bit yesterday even went with a sample of the *****s then the consultant told me to take a 12 mm okay fine he knows what he was talking about just to get home to try and fit it here the drill bit is big for my drill so I went this morning to go and return it the guy told me no we can't take it because of the packaging I mean like for real? How the **** was I suppose to fit the damn drill bit in my drill? Without opening the packaging now I must sit with a drill bit which I won't need this is really ridiculous