You can do it yourself, you do not need to contact SE support. Here is how:
Log on to Mogstation or go straight to SE account management (not XIV account management.)
If you went to Mogstation, click on [Square Enix Account Settings] then > [Account Information]
Next you want to scroll down and find the [Services and Options] and click on [One-Time Password]
Since you have a physical token, click on [Security Token (key ring type)]
Then next you'll click on [Security Token Removal] then click next and follow the rest of the instructions, after that you'll need to download the phone app and follow it's instructions or the ones on the account page on how to register that one. Hope this helps!