Well it might be your friend on their who is allowed that is messing with you. Or it might be someone you added and you totally forgot and he left the plot. You never know!
You cant have your plot hacked... Chances are, you added someone to the plot. Or someone cracked your account. Chances are, this "griefing team" is just a bunch of 11 year olds.
Which are? If they're personal, don't tell me. If they're to do with the plot, or if you're getting griefed. Report it.
How can you get greifed from yourself? If he cracked his account there isn't anything Minetime can donate for him.
LOL? Brake the sign? You probably just wrote that down there :O it looks like your the only one added. It does look like a threat that somebody is about to grief your plot with a banable offense ?
Apparently you can't get banned on creative for grieving, because you gave them perm to build, so it's your responsibility to take care of it, not staffs.