Sweat Equity worth?

I entered into an LLC and was told that I would get a certain percentage (nothing huge) for my sweat equity. I signed an agreement with this and was asked to do work and updated weekly as to our progress. I did the work for over a year (logged everything) and then suddenly the majority owners decided they wanted to go another direction and do not need me any more. They locked me out of everything and were ignoring me for weeks. Finally, I spoke to one of them and they said my percentage is now worth nothing and that all the work I did was for nothing.

Can they do that?