Provision (purchase) a phone number

Provisions a number and debits its first month's rent plus a one-time activation fee, as one purchase (see GET /v1/pricing for both amounts; the activation fee is the same on every tier and is not refunded on release). A balance that cannot cover the total returns 402 INSUFFICIENT_BALANCE before anything is charged or ordered. Accounts are capped on how many phone numbers they may hold at once (counting ACTIVE and SUSPENDED), a per-account limit that falls back to a platform-wide default staff can change at runtime; exceeding it returns 403 NUMBER_LIMIT_REACHED with the limit and current usage in details. Request a higher allowance from the dashboard. May also return 409 PURCHASE_IN_PROGRESS when another purchase for this account is already in flight: this is transient, unlike the terminal 409 CONFLICT returned when the number is already owned; retry PURCHASE_IN_PROGRESS after a short delay rather than treating it as a failed purchase.

Requires phone_numbers:w.