I was a twilight loader before going to seasonal. The steward seemed pretty upset that I wasn't getting paid and said he would take care of it. Also, another guy that I loaded twilight with became seasonal the same time as me and hasn't gotten paid either. I wasn't aware seasonal drivers were not allowed to file grievances. The steward didn't mention anything like that to me, maybe because I loaded twilight?
They might try and
with you during your probationary period; the union can't do much about the company DQ'ing someone. It's not impossible, but it's hard to prove retaliation over someone being DQ'd.
If things aren't moving fast enough, you should call Dept. of Labor Wage and Hour Division (
http://www.dol.gov/whd/) as this will make them act with a sense of urgency in getting you your corrected pay. If you've already filed a grievance, you might as well launch a missile, too. While UPS might not really care (in the grand scheme of things) about labor charges, they still have to pay their lawyers a lot of money to answer them.
Your center management team needs to really understand and re-learn the importance of making sure their people are paid for hours worked on a conference call with your area labor manager.