WhyIsMyEmailLate is built and maintained by one person, so messages go straight to the developer. Real reports are the best way the tool gets better, and every one gets read.
Tell me which mail service produced the message (Gmail, Outlook, a corporate gateway, something else) and what the tool showed. Please do not send the full headers with real addresses in them. Replace names and addresses with placeholders and keep the timestamps and server names, which is what the parser needs.
Typical reply time is within a few business days. For how the tool works, see How It Works or the Learning Center.