How long does it take to get a email back from customer support?

[worldofneil]

I changed my internet provider recently. Could that be the reason?

If you're not using two factor authentication (one time password), then yes.

Accounts without a one time password get frozen if they login from a different location/IP until you change your password. From what I understand they do normally email still though so perhaps it's in a spam filter somewhere? Or perhaps the email on the account isn't what you think it is?

Either way, just try resetting your password as that's usually what you have to do:

https://secure.square-enix.com/account/app/svc/reminder

Although if the email address on the account isn't current then this won't work sadly.