Payment lifecycle

pending means nothing qualifying has been seen. confirming means a transfer was seen and is waiting for confirmations, or the confirmed total is still short. paid means the confirmed total matches. underpaid and expired are decided when the invoice expires. overpaid means the confirmed total is higher. needs_review covers the wrong asset, a late payment, or a reorganization after a final status. failed is reserved for invoice creation, not an unpaid invoice.

BSC testnet and mainnet require 15 confirmations. That is an operational rule, not a claim of finality. Send only the requested asset on the network shown on the invoice.