Phoneburner purchases numbers from a vendor and sometimes numbers are not available in certain areas or can be back-ordered if they are popular.
Some area codes that are no longer available for purchase or have not come available in an extended amount of time (years)are:
934, 640, 820, 927, 212, 223, 680, 907, 986, 364, and 838
Some that are popular and in high demand that will put you on a waiting list for the number at this time ( as of 7/15/2020) are:
927, 303, 659, 718, 220, and 332
We can't guarantee a time frame for these numbers if you order them, but they will come up eventually when you are on the waitlist. If you do not want to wait, please email support (firstname.lastname@example.org) and let us know if there is another area code in the same area you would like to order and which one you would like to replace.
A complete list of North American Area codes can be found on Wikipedia.