No confirmation email week after payment was made

I registered for the IELTS exam last Monday, made a payment last Tuesday morning, but have heard nothing back from them. On their site it says they'll send you a confirmation email 24 hours after payment. Well, no email has come. I have written to them last Wednesday, but have yet to receive a reply. Big surprise. They take over a week just to reply to an email. This is no council run by British people, I can tell you that much.