Can I block entire area codes from my iPhone? I get 4-5 telemarketer calls each day.  Each time they call, it is from a completely different phone number.  Including different area codes.

I've performed all of the usual procedures to combat this.

•  Contacted my carrier (AT&amp;T).  They will block 30 or so numbers for free but then it costs after that.  This is useless because I get 30 different numbers in a week.  AT&amp;T suggested changing my number (for a FEE).

•  I've changed my number.  It went from bad to worse.  I actually get more on this new number.  I swear I don't put my number out there, I don't sign up for garbage, etc.  

•  I've tried telling these "companies" to remove me from their list.  They immediately hang up on me when I do that.  I've tried calling the numbers, it never goes through.  They are unreachable.  Even AT&amp;T admitted they can't track them.

•  I've registered for the national "do not call" registry.  This hasn't helped at all.

I'm running out of ideas.  I'd love to just turn my phone off but I can't because of work.

For each number I get, I immediately add it to the block numbers.  But this only stops repeat numbers.

So, my question is, is there a way in iOS to literally block entire area codes?  I seriously don't care if I block a few legit numbers for the sake of sanity.  I sometimes get telemarketers from my area code but those are more rare.

I have an iPhone 6 with the latest version if that helps.
Yes, there IS a free and easy way to block incoming nuisance calls on an iPhone!

(1) Get and install a silent ringtone (I use one called "10 seconds of silence" which I found on the internet for free).
(2) You know who your regular callers are. Give each contact a ringtone other than the default. (Yes, it takes a few minutes, but it's a one-time thing.)
(3) Set your phone's default ringtone to "10 seconds of silence".

From then on known callers get cause your phone to ring with whatever ringtone you've assigned that particular caller.

Calls from unknown callers will not cause your phone to ring. These callers can leave a message if they wish. Most spammers don't bother.

Repeat nuisance callers can have their numbers added to a special "Spammers" contact which you can block so that such callers cannot even leave messages. Just remember that if you do this, you have to unblock and re-block this contact each time you add a number. Don't worry about whether you indicate the number is fax or mobile or whatever--doesn't matter. I used to do this last step, but found it was unnecessary. Plus I kind of like to look once or twice a day and see where the spammers are ostensibly calling from--of course, their really using spoofed numbers using VoIP over the internet.