First of all make sure you fill in all your account details on this page.
This is not a uncommon case, however not within our reach. What you can try:
- Try the first option (non 3D secured payment) [1]
- Try 3D-Secure payment (last option) [2]
- Try a different card with options [1] and [2]
- If it does not work, you can pay with Bitcoin, iDeal or SafetyPay (Bancontact). To use Bitcoin, you have to buy Bitcoin, send it to a wallet app like BitPay, then with BitPay you can just scan the QR code to make the Bitcoin payment. We have a short howto available.