I'm sorry to hear the sad "fake brush" story above.
I also fell pray to a fake Mac brush seller on Ebay and bought a "187".... (I actually didn't know that it was a fake, when I bid on it. I thought that I could save some serious $, like I had with other stuff that turned out fine.... but it wasn't meant to be with this transaction.)
The pics in the auction looked like the real deal.... but it was a small pic anyway and could probably fool anyone. Once I got it in the mail, I became skeptical. It looked less full and fluffy than the one in the pic on the MAC site.
I washed it immediately - like I do all new brushes and that's when all hell broke loose. The brush shed and bled dye like craaaaaaaazy and I must have shampooed it like 10 times, hoping the bleeding and shedding would stop.... but it didn't. (I usually only shampoo a new brush 2-3 times and after that no more than 2 times.) My sink looked like I had given a somebody a dye job and a (full headed) hair cut.
Later that week, I went by the house of a friend who owns the same brush. She had bought hers, several years ago at a MAC demo. What a difference!!!
Well.... luckily I was "only" out $20 and I was also able to "salvage" the brush. I now use it to sweep away e/s flakes from my cheeks, which was not what I had bought it for... but I refuse to toss it quite yet.
Despite the fact that I had this trouble, I'm still interested in getting a REAL MAC, one day........................
Before I forget..... the sellers Ebay ID is mandy06shop