If you report too much times, maby the Moderators will IGNORE your reports, try to E-MAIL to an Moderator for him to look at the situation or that maby there's not enough Moderators or they don't have time to resolve your problem.
If its just you who reports him, the Mods may ignore, you should talk to the spammer (KINDLY) or tell other people to report him.
(He will not get banned, but muted for 1-20 days, it depends.)
P.S. Muted means that he will not be able to post anymore.