I can't remember, but if you're on probation you may not be allowed to vote. No dig intended but I seem to recall a pilot in his first year with the company is not a full paying member and therefore cannot vote, and yet I might be wrong.

But if you have not yet received your ballot by now and you're still on probation, that might be the reason. If you cannot get access to the ballot as explained above, call the union and ask about it.