There is an issue with your Electronic Arts account CANT SUBSCRIBE.

@Arodema 

To fix the account You need to reset the password on the linked EA account persona  ladrielle that has been disabled, that account uses a gmx.de email address

use the following link (insert the gmx.de email address) to reset the password then login on that EA account to fix the swtor account for purchasing

for future purchases, use incognito mode on chrome initially if you purchase on swtor.com to be sure browser cache and cookies is cleared