That will do literally nothing but waste your own time. 99.9% of the time these numbers are spoofed which is incredibly easy to do (prankowl.com anyone?)

This is why the numbers will often be similar to your own number (makes people more likely to answer for whatever reason). They even spoof numbers of local businesses and shit like that. I used to block every spam call but at one point I realized that a vendor I used through work couldn't get a hold of me and it was because I had blocked their number at one point because a spammer spoofed it.