I appreciate you highlighting your personal responsibility in the post, and hope you get your money back.
I think the uberfest organisers / backstack dortmund made one large mistake in under-estimating the level of demand for the lan, I think it was reasonable for them to expect a high level based on Poland.tf in the summer. Since this point I think they have done their best to rectify the situation.
I will say, if I remember hearing correctly, the Polish and German basestacks are very seperate businesses and generally poland.tf was very well organised and ran, so I wouldn't write off the Polish guys based on your experience with this.