We're really sorry you're having issues with our website!
The most likely cause of this would be that one or more of the fields on the payment page isn't populated properly.
We would suggest checking that all of the fields are filled in correctly and if there are any red boxes around any of these fields, please pay particular attention to these and make sure they are populated.
If you are still experiencing issues, please contact us using the message button below and we'll do our best to fix the problem.