I had this problem too. Tried 4 cards directly on website, and on Paypal. All get declined. Called our banks, all said they have unblocked and allowed exceptions to buying from this webstie (since it goes to Germany - they had it denied for fraud reasons.) Tickets been unanswered for a long time now.
e-mail support isnt instant, its going to take some time. not only that but your going to have to wait for a stable build to be released anyway,