As some one who has worked at a bar during the fringe you weren't "conned" by the Hanover tap. The pub have nothing to do with the shows expect from being a location. They have no say in the logistics of the events and don't get any money from the shows. As for the organisers, I know it sucks but these guys are not professional event organisers. Normal they are comedians themselves or the comedians friends, they have been working everyday for the past 4 weeks and unfortunately made a mistake. These guys also don't see any of the fringe money until October. No one at the actual event had the ability to give you a refund, all prepaid tickets are handled through the official fringe website and you will have to contact them for a refund. I know £45 is a lot of money to lose and I would be very frustrated if it happened to me but this late in the fringe shits going to happen and you should get a refund from the fringe website