O'Malley's Screwed me over yet again

I should have known that it wasn't going to work out.
About a month ago Brian the manager at O'Malley's Ocean Pub (using the whole name so this might hopefully show up in a search)asked me if I'd like to work a beer tub for the 4th of July. I'd always made mad money on the 4th because it is such a beach holiday. Being that O'Malley's ocean pub is located on Hollywood Beach, Florida (maximizing search keywords) it is pretty busy there on the 4th. I happily agreed to work. I loved being a bartender and still wish that I worked there. I had a great time, made great money and there are plenty of really great people who work there and hang out there. So, getting geared up and ready for working today, I spent the last three weeks designing and making a new outfit and making sure to let everyone know they needed to stop in an see me at the beer tub in front of O'Malley's Ocean pub.
Well at about 11AM today, July 4th my friend Veronika calls me to let me know that that Brian had asked her to call me to tell me that they have given the beer tub spot to another girl and thanks anyway but they no longer need me to work.
I guess to them it is no big deal, but to me it is a very big deal. Firstly, I need the money and was counting on the extra cash. Secondly I feel foolish that I spent so much time and money making a complete outfit. I was also looking forward to being a bartender again even if it was just for the day. So, I'm pretty depressed about it now.
I was really upset when they wouldn't hire me back after the baby and I'm pretty sure that what they did was illegal and this most recent screw over just reminds me how unscrupulous and unprofessional the management is at O'Malley's Ocean Pub in Hollywood Beach, Florida.
I think it is pretty weak that Brian didn't call me himself. He told Veronika that it was Joe Udell (the GM) who made the decistion and that he didn't find out until then either. Trying to shift the blame to Joe. I am positive that it was Joe who did make the decision because he hates me, but I think it was weak of Brian to not bother to tell me himself and make Veronika do it. He expressed to Veronika that he was so sorry and that he felt so bad, but I think if he felt badly he should have called me himself. And one of the reasons to go with the other girl and not me was that she had taken off work from her stewardess job to do it. What about me? Doesn't taking off from being a mom count? obviously these men don't understand what it is like to try and arrange for childcare on a holiday!