FACEBOOK PLZZZZZ HEEEEEEELP!!!!!!!!!!?

i blocked a person because he made some racist comments on one of the pics of my friend, i mean bellow my comment, i was abused by his racist comments and i blocked him; i've just unblocked him to see whether he has posted something else, smth. bad, i found out he deleted his S**t comments but i don't want him to find me again or write some more ****, im trying to re-block him again, but it doesn't work FB says try again later. plz is it possible to re block a person on Fb????? :((((