Message lifecycle & statuses - PressOne eSIM Developer Platform

POST /sms/send → "accepted"  (provider accepted; wallet provisionally charged)
        │
        ▼  provider delivery report (DLR)
   ┌────────────┬───────────────┐
   │  "sent"    │  "delivered"  │  "failed"
   └────────────┴───────────────┘

Status	Meaning
`accepted`	Returned by `/sms/send`; handed to the provider, no DLR yet.
`sent`	Provider accepted/submitted to the carrier; not yet confirmed delivered.
`delivered`	Confirmed delivered to the handset; `delivered_at` is set; cost trued-up.
`failed`	Could not be delivered; `error_message` explains why; charge refunded if the send was rejected outright.

Status only ever moves forward (pending → sent → failed → delivered by rank) — out-of-order
provider reports never downgrade a message that's already delivered.