Hello Rob,
we've had a few cases lately where the credit card wouldn't be charged successfully in our webshop, but when charging it in our backoffice it worked perfectly - according to our payment provider this is due to restrictions for online transactions that some credit cards have.
So what we can offer you as a quick solution is to process your order in our backoffice. You can email us your credit card details, for example in a password-protected PDF and the password in a second email, simply send these mails to sales@vsl.co.at with the details of your order.
Best,
Paul
Paul Kopf Product Manager VSL