Hi!
Tell me about it, I was in the same annoying position as yourself, I tried the TUC but to no avail, as they said,,,"unions are a law unto themselves they cannot interfere!!", Ive basically been given a bad Compromise Agreement deal, ws offered 19,000 but had tax off that and ive been given �14,000!!!! and have been forced to leave my job, where I did nothing wrong, as Ive been overworked basically anyway, I am at the stage of talking with the Community Legal Services Direct team, I have told my complaint and, if you feel your Employer or Union has not treated you properly/had your best interests at heart, try speaking to the CLS team.
Good Luck with everything - best wishes