digitalv - 9:22 pm on Jan 18, 2011 (gmt 0)
This seems like a pretty easy one to fix... if they filled out all of the info, then contact them and ask.
Does your website show the shipping information after collecting their address? Is it too high?
Is it possible your website is sending the users to the wrong PayPal account? Maybe the users DID check out and pay...
Have you tested in different browsers? I've successfully made sites that work great in Firefox, but you load them in IE and some required Ajax thing just doesn't load. Oops.