unfair practices

i worked 17 yrs. in union was promoted to supervisor with the understanding i would not lose my seniority, but i wouldn't gain any, and would not lose any.but now under a new contract between union and company they now if you keep the the supervisor job after 4/15/00 the date of the new contract you foreit all right to go back to the union,if you took the supervisor after 1990,people who took company jobs before 1990 are grandfathered. but after 1990 they are not . there are about 20 people this effects,is this fair and legal to grandfather some and not others? there are more details if needed. please help

Because you are represented by a union, you would need to address these issues with your union officials through the proscribed grievance process. Once that process is exhausted wiht no satisfcation - your claims should be directed tot he NLRB.

can a union or company change your senioritydate which is your hire date.? which puts people ahead of you on the seniority list that were hired after you.