Remarkably similar experience. I worked as a bag boy at a grocery store many years ago. The guy who hired me told me he strongly encourages everyone to join the union and I didn't realize at the time it was an implicit threat. After four months I kept wondering why there were five bag boys on duty and I was the only one working and where they went. One of the store managers came over to me during one of my shifts to thank me for my hard work. I was literally just doing my job while the other kids weren't. Less than two weeks later I had no hours on the schedule. Assuming it was a mistake I asked the guy who scheduled the hours (Mr. "Strongly Encourage") and he said he'd look into it. It was the end of my week so I needed to know what time to show up on Monday and so I persisted and said I needed to know when my next shift was so I wouldn't be late. He kept feigning ignorance. After my third inquiry he turned and said "Look, someone else transferred in so they got the hours, okay?"

I might still be on the payroll with no hours scheduled at that company for all I know.

This was definitely a case where a union wasn't good for workers -- it was good for the lazy bums who didn't want to work.