Teegrins, annewandering!

You mention PlayOnline. Does that mean you've been trying to use the PlayOnline Viewer for this?
If yes, then it would be normal that it fails.

It is not used for any account related stuff at all any longer, and you would need to use the Support Centre/Center instead:

Europe:
  • http://support.eu.square-enix.com/contacttop.php?id=455&la=2
Japan:
  • http://support.jp.square-enix.com/contacttop.php?id=11&la=0
North America:
  • http://support.na.square-enix.com/contacttop.php?id=20&la=1
Global:
  • http://www.square-enix.com/

I hope this helps~
Good luck!