Posting bot attack

There was gotta a member on my forum,he gotta the time between one post and another he need wait,
Then maybe he gotta some tools like posting bots or write it himself to post on my forum automatically.

Eg. My post time controled to 59 seconds, he will post the topic every 59 seconds , to all my catagorys and forums.

I banned then he will registerd backing again.+ I'm tired.

The morning I waked up,my forum gotta his spam even more pages!!

Then he said I ve nothing to do with him.

I'm so anoring!