If you want to stop paying your union dues for some reason, for god’s sake, do not just ignore the invoices. REQUEST AN HONORABLE WITHDRAWAL.
If you neglect to do that, guess what happens: You are considered SUSPENDED after a while. When you try to catch up, you may wind up having to pay an exhorbitant amount of back payments, all at once. In some cases, you may have to completely re-join, for the even more exhorbitant initiation dues. AS IF YOU NEVER BELONGED IN THE FIRST PLACE!
If you accept an audition, knowing you are not in good standing with the particular union that covers the project, you must determine (with your agent’s help, if necessary) if it’s worth paying off whatever you owe in order to earn the fee associated with this job.
The same principle applies if you are still in the must-join category. Can you afford to join for $2700 in order to earn a paycheck of $800? You’d better be. After all, if you got so far as to be a must-join, you knew the day would come when you actually had to give someone your dues. You should have been saving for this day all along.