I had the same problem and you have to bring it to your provider's attention. For verizon it is
spamdetector.notcaught@verizon.net which I got by googling 'verizon spam' or something like that.
I had this guy who wanted everyone to know about his blog and sent pretty much every other day, even after I asked him politely (and then not so politely) to stop. After 2 weeks of it I found the verizon service, never heard from him again.
I also find that getting your email remotely through the internet rather than through an app (I use Outlook Express) gets you a chance to look your email home page and you can find not only options for reporting spam but you also can open your spam file to see what is there. For instance, I'm in the apartment business, so occasionally a prospect's email gets put in the spam file. I have both verizon and comcast accounts, so I do this frequently.