If you are unsure about whether your payment went through correctly here are some indicators.
You have definitely paid if ...
1) You have received a confirmation of payment via email.
2) You have received an email from us with your document attached.
If neither of these things have happened and you are sure your email is working correctly it is very unlikely that your credit card has been charged. Of course if you need to be 100% certain you can contact your bank and ask them.