Yeah, same thing happened to me i just let him keep talkin then after he added my pur card and insisted i trade towards a pre-owned game , baaaammm it popped up on the system and he said "oh looks like your pur card did do something" and he was shocked , mightve been why i called 2 hours later and he refused to let me trade in duplicate copys now hah . When i first call in the morning they were fine w/ doing duplicate /: but i didnt have any yet.
Yeah, better go to some other store and do it. I didn't buy anything from my store because of the way the pro sales dude was acting. Will prolly go after some time and get what I want.