GitHub is the only channel
Open an issue in the public repository and tell us what you found. You can also ask us there to remove a store or a product from the catalog.
We use that channel because it leaves a public, verifiable record of every request. We do not invent a contact email or a form we cannot answer.
What to include in your report
If you report a wrong price, include the product URL and the store. If you request a removal, name the store or product and the reason.
To suggest a roaster, send us the name and address of their store. We check that prices are public and that the catalog can be read without an account.