I PMed you already.

If your board is not heavily hacked, shut down your vB, change the password to your database, change the SuperAdmin user id to a new user id, change every Super Admin and Admin password and then re-upload the vB files and AWS files from the distribution zip file. More than likely this person has changed the standard vB distribution to allow him in the system even if he is banned or deleted from the database. That is not something that AWS does. AWS follows vB standards for authentication etc. It's your vB files that you should worry about most.

Enigma1234, the build-in vB system is far from being equivalent to AWS.

I think this guy is just throwing empty threats around, if you didnt know him before to be some brilliant hacker, chances are he still isnt one.

tell him to f$%k off! If he does hack your board, hes an idiot..
you have his threats, his IP address...
the second it happens call the cops.
internet crimes can give you a suprisingly lenghty jail sentence.

just back your database up once a week and you will be fine.