No geopanels. There's a bunch of zombies and Majorita is the boss. My characters are already 30+ levels above, so unless it's normal to need to be super overleveled I'm not sure what I'm doing wrong.
The Majorita missions are amongst the hardest missions in the main story, so your trouble isn't totally unexpected.
I use the Tower method to do these missions, as I think you can do them at a lower level this way than any other. Hard to explain in text but I'll do my best.
Tower method:
On turn 1, build up a 10-tall tower behind the base panel.
Do nothing else until zombies are within throw/move range.
Throw or Tower Move the tower as far as you can.
Have the new base Tower Release.
Have the guy who released and the first guy walk on to a 3rd unit, making a 3 tall tower, which is pretty close to an enemy.
Attack/Lift/Attack/Lift/Attack/Lift until you've used all but one unit. If your attack power is lower, Tower Whip, Fishing, and Laser will help you do more damage.
Have the last person pick the tower back up, and "Tower Move" back to your base panel, creating separation with the remaining zombies.
End your turn and do the throw/release/build tower/attack/tower move again on the following turn.
This works on a lot of maps to beat them with a really weak power level, but it's particularly effective against the Zombies because they have a short attack range and a low movement, and there are so many of them.