I worked for them a few years ago.
Try using a browser, if that doesn't work, clear the cache and cookies and try again. If it still doesn't work, try a different browser (the one they'd usually recommend was Firefox). If that doesn't work, customer service should be able to remove it for you.

The system is dumb, the security system is automated and did weird shit at times. One of the error codes in the document we had was labelled as 'WTF happened?'
So yeah. PayPal are kinda wang sometimes.