Hello all,
I too am in the same boat as a lot of you. I received this e-mail first thing in the morning (happy waking up) and immediatly checked my paypal and bankaccounts. These both verify that the payment has been made and that I don't own the money any more.
Worst of all: after I contacted support with excerpts of my paypal confirmation I just get an automatically generated message saying I should still pay.
I really hope this gets resolved soon and does not escalate in the revokation of keys and resulting disputes or legal action.