I was grifed and i know who did it but even if i untrust them they can still place signs and ohter things please help

 

If the player is in your coop, and online at the time, you can do /coop kick [playername]. Which will remove them from being able to modify the island.

 

^ As Blyx said. The players that you want to kick have to be online or else they won't actually be kicked from your coop.

 

the problem is she is never on...

 

Then I don't think there's much you can do unless you wait for her to come on. Or unless the coop glitch is fixed.

 

ok...

 

Vaulterplaysminecraft I suggest making a thread in Suggestions regarding the /coop command, I'm sure
many would appreciate it, and it will indeed solve your issue effectively.

 

Not when theyre offline.

 

Locking, as the initial question was answered.