It's part of the terms of service you agreed to when you signed up, that SE are fully entitled to take the game offline for maintenance whenever they need to, and for as much time as they need, without compensation to the player.

It's unfortunate, but no matter what time of day or part of the week they do it on, someone somewhere is going to always be inconvenienced by server downtime, and sadly you've got the short stick today.

This maintenance is also accompanied by a patch hence why it's also longer than normal.