Implement a complete ACH return code handler covering R01 through R29 with correct retry and notification logic

Steps

1. Subscribe to your ACH originator or bank API's return webhook or poll for return entries; parse the return reason code from the addenda record
2. Classify codes into three buckets: hard failures that require no retry (R02 account closed, R03 no account, R04 invalid account number, R07/R10 authorization revoked), soft failures that may retry once (R01 insufficient funds, R09 uncollected funds), and administrative codes requiring data correction (R04, R05, R08)
3. For R01/R09 soft failures, implement a single retry no sooner than 1 banking day later; NACHA rules prohibit retrying an NSF return more than 2 times on the original authorization
4. For R07, R10, R29, and R23 codes that indicate authorization revoked or not authorized, immediately stop all future debits on that account and notify the customer; do not retry
5. For R11 (check truncation entry return) and R14/R15 (representative payee deceased/unable), treat as requiring human review before any further action