You may also want to try disabling any browser extensions/plugins that you may be running as it's strange you can't open a ticket. I'd say it likely has to do with your browser or if you're on a VPN that could also be causing issues. You can always just shoot us an e-mail as well at contact@fakku.net and we can assist via e-mail that way!
But I agree with what Jacob said - try contacting your card issuer and letting them know you're trying to make a purchase as they may be declining it. Unfortunately, we rarely get any information aside from "contact card issuer for details" when it comes to cards being declined.