Error i2501
Suspicious activity has likely occurred on your account (different ISP, strange computers, strange browsers etc). You need to contact Square Enix support (recommended to use the phone option through the Mog Station) to get this sorted. You maybe required to to send scanned copy of documents to prove your identity which can take a while to process.
To prevent this from happening again in future, use Square Enix's one time password system.


http://www.wryven.com/wiki/m/4000356...ng#Error_i2501


Found this, not sure if it helps much if they don't have accounts...