I emailed this morning with EuroDNS Support which replied two times within 10 minutes.
Because the creditcard will be charged at once after submitting, i was wondering what would happen if i don't get the domain name.
Their answer was:
"If you don't succeed in getting the desired domain you will receive a refund to your EuroDNS credit account."
"The money will first be transferred to your EuroDNS credit account from where you can request a refund to your credit card." (a .com/.net/.org is â¬18 at EuroDNS)
about the Voucher Code:
I think you have first to make an account and then log in.
The voucher code is shown under the section "My Account" on the left.