It's true that Square "warned everyone that this would happen". However, that doesn't change the fact that they shouldn't be charging people for a service that isn't being provided.
One PR-friendly way to deal with this would be to give a blanket 10 free days of game time or so to people who signed up or reactivated characters during the affected time period. It cold be that they are waiting to see what the damage is on this before announcing any compensation, but it would benefit them to make some announcement regarding compensation sooner rather than later.
