Contact
Write to alberto@cuitodigital.com. That address is read by a person, and the most useful thing you can send is a correction: a line item you believe is priced wrongly, with the reasoning. Every estimated figure on this site publishes the assumption behind it precisely so that it can be argued with.
Reporting a figure you think is wrong
Tell us which line item, what you would expect instead, and roughly where you work. Regional variation is expected and already modelled, so a figure that looks wrong in your market may still be right nationally — but if it is wrong, we would rather know.
Changes to any dataset are recorded with a date in the change log.
There is no contact form
Deliberately. A form would mean collecting and storing personal data, and this site collects none. Email is enough.