I'm talking about a BM here, a BM bumping his threads with useless posts, not a newbie spamming for his sig or to rank up so it's not a mod but a DT that's needed here.
So report them to moderator.
Sometimes they use twitter reports to bump their topics, I've noticed and reported similar behavior several times already, just write in comments "they use twitter reports to bump thread several times per day" and report all bumps - but be careful,
if it is only one bump a day they are allowed to do so. Of course, they need to delete old bumps.