There are ways you can perhaps track the perpetrator.
An IP address can point to an ISP (internet service provider) and you hope it's not Wanadoo because they will just do nothing.
Sites such as
http://www.geobytes.com/ipLocator.htm can find a geographical location and I've heard there are better ones that can pinpoint as far as postcode.
However, the search is likely a waste of time. Check the numbers submitted before adding them to the database if possible, that should prevent unpleasantness like Angry Hackney.
PS: I utterly sympathise, I've gone through that myself.