I'm very sorry to hear about your mother's experience selling this product. I have recently gone on a search to check out the MonaVie reviews and they seem pretty mixed, although that is fairly common for any MLM company's reviews. It makes sense that with places like Sam's club and Costco producing similar products at nearly half the price, that it will effect the sales of MonaVie products. Unfortunately, I don't know that its entirely fair to blame MonaVie, and believe me I am not one to advocate too many MLM companies, you can tell just by reading my other posts, but I don't think your mother's inability to sell this product is a reason to feel that the company is a scam or did anything wrong.
Did your mother research Acai berry and superfruit juices in general before she invested thousands of dollars into her business? Did she compare prices to make sure MonaVie products was something she could sell? Competition is a part of any company, and all products have them. Sony has Microsoft as a Nemesis, Nintendo once faced Sega, McDonalds fought wars with Burger King, and the list goes on and on. When a company is successful, many other competing companies pop up with cheaper versions of products, and it takes a portion of the "killing" and slows down the stream dramatically. I wonder if your mother focused on finding what's better about MonaVie's product and emphasizing on the differences. There must be a reason why Costco's product is cheaper, right?
I think its shame to hear stories like these and I sincerely hope your mom gets back on her feet financially, but I don't think any part of your post was accurate in claming that MonaVie is a scam, or did anything wrong in regard to your mother.