You may have set yourself up right there. It used to irk the hell out of me when people would ask for blank decks. I understand not wanting to, or being able to pay for pro decks, but there is a big difference between a blank and a shop deck. Blanks are available on ebay 5 at at a time, and usually expire quicker than the milk you left out. Most places take pride in their shop decks, wanting to bring you a good board at a fair price. You go in asking for a blank deck, I feel you are are being disrespectful to the shop, and to skateboarding. Not that they should act stuck up towards you, but I would certainly take a minute to tell you the difference between the two.
If you adjust your vocabulary, you may have better luck, because a shop deck is not a blank. Or maybe they just didn't like the cut of your jib. Or maybe they are dicks. I don't know. The couple of guys I've met from there have been all good towards me, but that doesn't mean a thing.