I have the exact same problem. I tried renewing the subscription yesterday without success. I entered my credit card information in the Mog Station and then then it said that you can now go change your payment method. So i go here https://secure.square-enix.com and check it out, but it asks my credit card information again. So i enter my card info again and it again says you can now change your payment method. I have no idea where so i go and put the info once again to Mog Station and then i get an error like this:

ERROR (-24202)
A technical issue has occurred.
Try accessing the site again. If the issue still has not been resolved, please contact the Square Enix Support Centre.

I check my bank account and each time they charged me 1 €. Well it's not charged yet, it says "reserved".