I have bought a couple of Plissons from Atkinsons. I too spoke with JJ and got great service. OTOH, I bought brushes that were in stock. A friend of mine ordered one that was not in stock and had to wait a couple of months.
It is my impression that they do not charge your credit card until they receive the brush from Plisson. I would telephone and ask for JJ. He will undoubtedly clear things up for you. Make sure you mention the forum for the 20% discount.
"We shall not cease from exploration And the end of all our exploring Will be to arrive where we started And know the place for the first time". T.S. Eliot