I think this is more likely! I have had members, clients and people that simply must enjoy messing around; not being able to complete payment and saying the form is not working; when it's clear to see it is and PP processing has even been tested thoroughly by myself to make sure prior and after ...
Some people will not take a few moments to try or understand how to make payment and jump right to "it's not working" or "I can't do it" .... it's a pain from our point of view and leaves us thinking WTF as we know damn well it's working....
I could be wrong about this in your case but I think it's more possible than not!
The other night it took me almost 45 minutes walking someone through making payment for SSL Cert because they simply could not be bothered to read and follow steps correctly and they was telling me it was not working for them (and they was in located in the USA so should understand English and simple PP instructions) .... it's very frustrating and should have been done within 2 - 3 mins :/
or they just don't know how to operate the form
DedicatedServer4You.com -- BIGGEST Range of Dedicated Servers at the Lowest Price!