Message fron NALC: 

Votes in the rank-and-file ballot referendum on ratification of the tentative agreement for a new five-year contract must be received by the Ballot Committee by 11:59 p.m. on August 27 in order to be counted

However, the deadline is being extended to 11:59 p.m. on September 6 for 16,630 members whose ballots were misaddressed due to a problem in the mailing software, as explained in the latest NALC Bulletin.

A list of affected members and their branch numbers is posted here. If you are on the list, a new ballot has been mailed and you will be given extra time to vote. If your name is not on the list and you have not received a ballot, contact your branch president immediately to request a replacement ballot.

source: http://www.nalc.org