I don't know if this applies to anyone, but figured I'd mention it as an FYI- if you're a person that's won in a pre-[C]A 2.0 Bro sale and this is your first [C]A 2.0 win, the invoice link is automated and is now included in your winner notification message (also available through the website I believe).
I caught it quick last time I won, but if you're someone that just skips over everything to see what you won, you might've missed it.