I know from personal experience that it is very hard to get someone out of an MLM
I was dating a guy that was in up to his ears in Primerica. I thought that going broke would cause him to leave the company. He switched all within the same MLM so he could work and still be part of the MLM. I got him to move 50 miles away (which means you lose all your customers) but he simply stepped down from his high ranking to a lower ranking prostion to retain the customers. Now he is trying to turn the company he is working for into Primerica. He is buying some of the books and giving them to his boss (so he can run the company the “right way”).
One day when we went to horrible talk (actaully it was a plea for money) given by the Audobon Society. I wanted to leave and he told me I was being “negative”. I said the talk was stupid and pointless and I did not want to waste my time. He told me that I needed to understand that some people aren’t good at presentations and I needed to change my thinking to become more positive. Later the same day he tried to get me to listen to positive thinking cds.
The point is the brainwashing is powerful and no person wants to admit that thier “friends” used and manipulated them. Your sister is being told she is a loser if she quits and not to communicate with losers. It is a long hard road to get someone to get out of a MLM and stay out. However since your sister is new to the scene it might be easier to get her out. The most important thing is to get to counseling so a trained professional can get her to see the light. That is the only way that I have seen that works.