This has moved beyond spam to an attack of service.
TMF guys...who hates you enough to shut you down? No spammer posts virtually identical posts every five minutes for days (I'll give Alstry some slack here). =0)
Use Captcha, reject their servers, get an intern to sit and kill totally the posts as fast as they appear and/or get an internet EXPERT to program a system to trash these as fast as they appear.
These clowns are attacking a significant part of your business model.