The Bans page keeps copies of your server's ban list, so bans a raid or a rogue admin lifted can be put back. Only the server owner can start a restore. If you own several servers, you can also keep your own ban list and have the servers you own follow it. A server only follows the list while you are still its owner, and taking someone off the list only lifts the bans the list itself made.
Members' roles have their own backups. Open the Snapshots page to find the server owner's member role backups, and restore the roles members held before an incident.