Nitrogen instead of Argon

Hey I went to get Argon for my first refill and I did not notice until I got home that the bottle says Nitrogen on it. I looked at the receipt and it says NI 150 that is the size of my bottle. He picked up the bottle and read Argon out loud so I did not think he would have mixed it up. Man I wanted to weld this weekend....I have to take this back right? Would I have blown myself up if I tried to hook this up and weld without knowing?

Dax,

Nitrogen is not a completely unreactive gas and has been used at times for various types of shielding gas. You wouldn't have blown yourself up (at least I don't think so), but you would have fun trying to weld with it. lol.