HTTP 402 means payment is required. It does not mean payment happened.
For current SML x402-v2 resources, request the target first and read its fresh PAYMENT-REQUIRED challenge. The caller decides whether those exact terms fit its spending policy and, if so, retries with the matching PAYMENT-SIGNATURE.
Current SML default rail: Base mainnet eip155:8453 and USDC. Never use a cached article, old wallet, deprecated header or unrelated chain as spending authority.
After authorization, verify settlement and accepted delivery separately.