Short update...
48 hours have passed since my successful order now... The product is still in my Account (incl. Order-number, etc., Status pending)
Still no email... Nothing!
As advised I've contacted the SE Store Support via Form and via email.
Guess what? Ya..., right nothing either!
They shouldn't only take our money, they should also support and reply to their paying customers.

Are there any other ppl, that still wait on the mail?