Hi EtherealN, firstly thanks for coming on here and doing your best to calm the situation. I too have received the email, and I am also showing completed Paypal and Bank transactions as others have mentioned. I purchased FC3 on 24 April, just 5 days ago.
I think the tone of the email sent doesn't help, it comes across rather aggressive towards customers that have made a purchase in good faith, and demands their action in under 1 week or they forfeit their purchase.