Two options are available to you. I recommend you only use one:
1) Check the 3 'Accept xxx Bans' flags in your account manager. When a player is caught cheating on a server streaming to PBBans, the ban command is sent to your server. Note that you must first generate a ban list from the Master Ban Index and upload it to your server first.
2) Check the 'Enforce Bans' flag in your account manager, and you don't have to do anything. When a player connects to your server, their GUID is checked against the Master Ban Index. If they are banned here, they are kicked and banned from your server. Not only does this mean you don't have to generate a ban list and upload it, but your ban list is kept much shorter and therefore your server runs more efficiently.