What's funny is that even if you place your number on the DNC list, that is why the spammers are using normal area codes - it bypasses DNC list. DNC list is only for 800 numbers and such. If you use a normal area code, spammers will not be blocked out - that is their workaround to DNC list.
Unknown spam from Canada bypassing US law. Phone solicitation companies are setting up out of country to bypass US law on calling/ texting cell phones.