He made a 1x1 tower (possibly 2, I didn't bother to check the other one) to get to the sky city I was helping to build. And he just left it there. He griefed through the base of it to get inside. He then made another 1x1 tower to get to the main level of which he griefed through. Then dug a few random holes on the ground of the main level. And then griefed through the floor of one of the sub platforms which I assume he probably used to jump down to get back to the ground.

If you ask me, 3 days doesn't seem like enough. It was a fine display of inconsiderate griefing.

It was a minor grief, so it was just a day. And this belongs in the ban appeal section :]
You can request for an admin to unban you earlier.