I've entered the wrong Security Card number three times and I have been trade-locked.

If you have been trade-locked from entering the wrong Security Card number three times

either get it re-issued or cancel and apply again.

1) How to Re-issue Security Card: Click Seria in game and then click Security Card re-issue. An email containing a new Security Card will be sent to your registered e-mail account.

2) How to Remove Security Card: Please go to [My Account > Security > Security Card] on the home page to proceed with Security Card Removal process.
You cannot apply for a new Security Card anymore. After removing your Security Card, please use another secondary verification system.