Yesterday, while perusing the forums I came across this post. There have been several account center maintenance periods lately, in which they were transferring over to the EA Billing system. The important part of this is that, for security reasons, no billing information was transferred. That means your subscription is no longer set to renew (maybe not, continue on for an UPDATE).
I logged in to verify and that was the case. I had to re-enter my payment details to ensure I'd have access come next billing period. You'll also have to link your Mythic account to an EA account. Kai mentioned we should be getting an e-mail about this soon.
UPDATE from Kai:
A clarification because I noticed that my post can be misunderstood:If you have a recurring subscription and never ever log into the account center, nothing will change for you. Your account stays on the Mythic account center and your subscription will continue.If you have logged into the Account Center since last Wednesday and have linked your account to EA (or if you will do it from now on), in this case you will have to submit your billing details again. The payment details are not automatically transferred.
