curl -X POST "https://demo.api.vultlocal.com/api/v1/subscribers/sub_abc123/block" \
  -H "Authorization: Bearer olive_live_xxx" \
  -H "Content-Type: application/json" \
  -d '{
    "reason": "Suspicious activity detected - multiple failed PIN attempts"
  }'

{
  "success": true,
  "message": "Subscriber blocked successfully",
  "blocked_at": "2025-01-20T14:45:00Z",
  "blocked_by": "admin@olive.sl"
}

{
  "error": "Subscriber not found",
  "code": "NOT_FOUND"
}