Whilst I understand you being pissed off, to a certain extent they're right. Much like jazz has its standards, rock and soul and blues have their standards. It's not unreasonable for people in those particular scenes to expect other people that play in those scenes to know the respective standards. This is a nightmare for someone new to the scene, and they shouldn't have waited until the gig to let you know there were no charts but, to be fair, maybe it would have been an idea for you to ask about charts in advance. An awful lot of jazz players would look at you oddly (to put it mildly) if you didn't know, say, Autumn Leaves; the same is true for not knowing Mustang Sally or Brown Eyed Girl in this situation. No offence intended.