By what method did you pay?
If you paid online, did you get an acknowledgement email confirming all has been paid? I paid by this method..........the amount came out of my account straight away and a confirmation email was received within 5 minutes.
Did you ring and pay by phone? If so, the person processing the transaction should have done it straight away for you. The payment then should have come straight out of your account if you paid by Visa Debit.
To be sure, I'd give them a call to check it out. It'll be no fun if you are hit with a penalty down the line!