The maximum payment is what you selected:



Mog Station only supports a maximum of 180 days of game time on a SQUARE ENIX account at any time.

If they took a payment one month a go, then you can't attempt to buy more time until you have 120 days remaining, so maybe check to see how many days are remaining on your account, if it had 0, then the charge was reversed already or your card was declined. It isn't possible to have over 180 days and if you got charged twice you'd have 360 days etc