Contact
This is a small, independently run tool — there is no support team, ticketing system, or phone line behind it, and no account to look up. The real channel is email.
Send an email
Include what you pasted (or a shortened version that still shows the problem), what you expected, and what you got instead.
Response times
This is maintained in spare time alongside other work, so there is no guaranteed response time. Every email is read; not every one gets a fix, and a duplicate or a request that is out of scope for a single-page converter may simply get a short reply saying so.