What to do when someone else is using your email address?

periklisv writes: So, I was one of the early lucky people that registered a gmail address using my [e-mail]. This has proven pretty convenient over the years, as it's simple and short, which makes it easy to communicate over the phone, write down on applications etc. However, over the past 6 months, some dude in Australia (I live in the EU) who happens to have the same last name as myself, is using it to sign up to all sorts of services. I daily receive emails from adult dating sites, loan services, government agencies, online retailers etc, all of them either asking me to verify my account, or, even worse, having signed me up to their service (especially dating sites), which makes me really uncomfortable, my being a married man with children.

I tried to locate the person on facebook, twitter etc and contacted a few that seemed to match, but I never got a response. So the question is, how do you cope with such a case, especially nowadays that sites seem to ignore the email verification for signups?