FYI,
1)   Don't even pick up the call ----- you are not obligated to talk to anyone on unknown phone numbers .    Surely you don't open unknown e-mail addresses, do you?
2)  if it's important enough your unknown caller should leave a message      
3)  if you happen to answer the call and the caller is a telemarketer, or is rude or pushy just say "hang on a minute" ( don't even wait for a polite opening ),  put the phone down, and later, hang up when you hear the dial tone.  
4)  are you being charged to call that area code 321 number to remove your phone number from the call list?    just curious      

TIME is the most valuable asset to telemarketers so the longer you keep them on line the more likely you will be removed from the contact list.   DON'T TALK TO THEM !!!   It works for me !!

Am now able to blacklist phone numbers on our Ooma system and set the system to continuously ring.    See Ooma.com

I believe this one from British Columbia was a private party mis-dial at midnight.