Probably because you posted in threads that got trashed.

If you've made a lot of posts in a thread and it gets trashed then your post count will go down. Don't post in unsubstantial threads that are liable to be deleted if you're worried about this.

That's probably because you post mostly in huge spam threads or other garbage threads, which are designed by the shitposting OPs to be easy for shitposting alts to reply to.  Stop posting in threads that have 50 pages--hell, even 20 pages.  I also have no sympathy for people who try to support themselves with sig campaigns, and it blows my mind that people are so desperate to get positions in them, and then, come post count day, you discover that they got booted or couldn't reach the minimum number of posts.  Being in a signature campaign isn't a terribly difficult "job".  I usually end up way above the minimum, precisely because I don't view this as a job.  And you, there's no excuse.  I work a full-time job and still make more than enough posts to get paid.  If you're unemployed and have an excuse, that's exactly what it is, an excuse.

The Pharmacist is pretty much spot on. Don't post in unsubstantial threads that are liable to be trashcanned and don't make the bare minimum of posts just to hit your quota if you're worried about not getting paid. Had you of made an extra ten posts you wouldn't have anything to worry about and this is the problem here. People forcing themselves to squeeze out as many posts as possible just to hit their targets before the end of the month over x amount of accounts which just leads to lower and lower quality posts.