"Brown" is really odd. eInk is black/white/gray. Could be the eInk emulsion is contaminated with another substance. I would contact Tech Support immediately (they're open 7 days a week) and arrange for a warranty repair while you still can. International warranty repairs typically take 2 weeks from send to receive back (based on a couple of reported cases on the forums) where you'll need to pay the shipping to the US, but they'll send it back to you at their expense.