I accidentally put in the wrong e-mail when I paid with paypal.
Could I possibly change it? Will it affect my order?
also it said on the page that I could contact someone through helpATfanimeDOTcom I tried, but I got a Delivery Status Notification that said it failed.
If you received a paypal payment confirmation, then your account was charged and there should be no problem.
If you mistakenly entered the wrong address while registering for paypal, then that is something you need to correct with paypal. If the account information was correct the payment should go through but the payment confirmation may have gone to the wrong address.
If you entered the incorrect e-mail address while registering for fanime, then that can be corrected and has no bearing on the payment transaction through paypal. to correct that of if you have any more questions, e-mail registrationATfanimeDOTcom.