mixed bag
They have always responded and helped me whenever I had a problem pre tribunal.
However, once you are in the actual Acas or tribunal process that's when communication is less frequent.
I would ask questions but not get a clear answer. Then when I tried to sort things myself - cause I didn't know what the union were doing - I'd get told off!
Also the union will ignore your strongest claims and supporting evidence in favour of what claims are 'easy' and the least work for them.
Then tell you off for not giving them all the evidence you have after specifically telling you not to bombard them with emails??
The problem is that you have no choice but to go along with what the union say because you can't afford alternative help. They say they'll support you throughout any issue but their preference is to settle - regardless of how rubbish that settlement is.