I think my fiancée and her co-workers are being illegally scammed by their management. Is it at all possible this is legal?

My fiancée is a personal trainer at a popular gym with hundreds of locations across the country. Recently, her district started selling this very shady product line of supplements. This product line also has a heart rate monitor arm band with an online subscription that goes along with it.

Just like any chain, she's pressured into selling these supplements, and subscriptions to the online service, to her clients. However, and doesn't believe in the value of these supplements. Not because there's anything actually wrong with them, but just because they're unnecessary and she considers them a waste of money.

After failing to meet the monthly quota for selling this product line and subscriptions, her management forced her (and everyone else who failed to meet this quota) to attend a training seminar for this product line.

Up to this point, the practices are crappy, but by no means illegal. Here is where things get dubious though:

• She and her co-workers are forced to attend this FOUR HOUR "training session," even though there was nothing in their employment contract that ever suggested these supplements/subscriptions would be a part of her job
• She's not paid anything, not even bare-minimum wage, to attend these four hour training sessions
• She had a legitimate prior obligation, and her management forced her to get a written note to get out of it
• If she didn't attend and have a written note, she'd get "written up" by her management
• If she gets written up, then her management threatened to not give them their already-earned commission for the entire previous month

The last point is the real kicker. How the fuck can that be legal? 60+% of her total income is from solely commissions. She already sold her sessions, spent hours giving those sessions to those clients, and now since she refused to waste her client's money on useless supplements, her manager is threatening to retroactively take the commissions out of her future paycheck.

If this is indeed illegal, what possible course of action would she have outside of filing a lawsuit? Some sort of Better Business Bureau for employees?

Suggestions to quit her job are obvious...that's already underway. :-)