Hey there,
Great application, but I'm sorry. You don't meet requirements to become a Moderator, you need to be a Helper or Donor and up in order to apply for this rank. Unless if Shahblox approves of your application, although you can still have a great chance of becoming a moderator. Anyways, the proper way to rollback a grief is this way:
/co rollback playername r: t:
playername: It could be the person who built the building, or the griefer. Try using the griefer name and see if it brings back the building, or the person who built the build. I'm not sure, sorry. I forgot. If you do get moderator, I'll tell you.
r: (The radius, this is far you want to bring back a grief. Ex: /co rollback Bob r:50 t:0h this will rollback the build by the player, within your radius.)
t: (The time, do /co i and then left/right click to get details. Once you found out who built the house, *You can find this out by checking the whole building and see who commonly placed or broke blocks, that'll mean that person built that build* and then the time should be like Ex: 072/h you would do /co rollback Bob r:50 t:72h )
Also, to ban players just do /griefer, /abuser, /hacker, /advertiser, (I believe those are all the commands) and then followed by the playername. Ex: /hacker Bob. The command will then ban that player.
Good luck buddy, You're capable of anything. And Moderator is one thing you can be capable of, and I wish you the very best and don't give up.
-Regards,
Legoboy31