Cannot Ban Steam ID

[Twiztid4Life]

alot of people who hack and like to cause trouble in my server come in with ` in there name more then once. Now i tried to ban there steam id but everytime i type in banid "Steam_ajfjakjfajfa" and it comes up "use 0 for permanant ban. Now when i put it like banid 0 "Steam_ajfakjfjafjafka" and yet it still doesn't get rid of the guy or ban him. Now please let me know what the command would be cause i am getting so sick of hackers in my server for 1.6 and for source. The server is not protected but does run HL Guard. PLEASE!!! help me man i'm begging you i'm getting so fed up.

your boy,
Twiztid4Lyfe


-[D4B]-