If I don't know the number I check Google. If it comes back as a spam call the number goes on the call block list - just like this one will. I also post all spam and spoofed numbers I receive out on the Internet. It helps others figure out if it just another low life scumbag on the other end of the line.
I have been getting a lot of AC 208 calls lately on my cell phone. The tactic is to call three times, hoping that I will forget to check caller ID or just pick up.
I have received calls from 297-7540, 629-4408, 297-7581, 629-0423 from Sept 4 through today, Sept 12.