I don't have a Dropbox account but I've recently been sent an email from Dropbox saying that my account has been accessed from another device. Thinking I had maybe signed up a while ago and forgot, I signed in and reset the password. When I logged in I realised that none of the photos or information belongs to me, but my email address is listed as the account holder. How can I let this person know I have access to their account ? I could delete the account but don't want to the person to loose all their photos. But I have no way of contacting them.
It wouldn't be possible to inform the user, since they are using your own email to login by mistake, believing it to be their own email. Perhaps there was a typo, or an extra dot or letter similar to their address, but there is no way to know, and I wouldn't recommend trying to contact them.
For your own privacy and security, I'd recommend removing access to the account from all devices via this page, and deleting the account completely.
If they create another account using your email, please let us know!