That's so horrible, I would be uber pissed if that happened to me. I'd say straight up to the girl, "Look, I asked you on a date because i wanted a date with you. Instead I got a date with your whole family, and didn't even sit next to you. Thanks for wasting my time and money, and embarrassing the forget out of me."
No actually, that story is enraging. That girl sounds really handicapped and I ended up picturing that really loving nerdy family that visited on icarly..I think it was their cousins or something but the younger boy had a cone on his head, they all had severe allergies at everything, were loud and obnoxious, and that's pretty much what I pictured.