I had a similar experience, funnily enough golf course memberships too. Doing minimal OSI work on the numerous emails I found the guy on facebook and friended him (accepted due to same surname I assume). I remember saying something like:
"Hi, I noticed you just signed up for an Epic Games account, and you happened to use my email address <lastname>@gmail. Would you mind not doing that, please?"
He responded that I was a creep and that it was his email, and proceeded to block me. I mean he might've been right on the former, but patently wrong on the latter.
In retrospect, I probably should have printed the emails and then sent those too. That may have been taking the bit too far, but it would have been much funnier from my POV.
The creep creep creep ;-)
I once got someone and their family's Disney World booking details sent to <theirname>@<mydomain>. It was a real thing, I could click the link and go view their booking at the official website. I have no idea what made that person to type out <mydomain> as their email, the domain is not even close to any publicly hosted email services or any company names. I kept getting more notifications of the upcoming Disney World trip so I ended up disabling that particular address so that those emails bounce.
I sent a few emails to his family explaining this, they told me that I was wrong. I gave up and just ignore all of those emails.
It's on gmail and I don't use gmail for important things anyway...
What a bizarre response... somebody who isn't the person you intended to email has replied to you from the address you sent the message to. What could possibly make someone think that the person replying is the one who was wrong?
In their minds, they did email their brother, and the weird guy who replied is wrong. It might be possible, with enough investment of time, to help them understand how/why it went wrong, but as nicolas_t experienced, it is sometimes easier just to block them and move on.
I was lucky, I was a Hotmail early adopter and I regularly receive emails for two namesakes. I was able to figure out their correct email addresses over the years and they are both tech savvy enough to understand the issue. I forward on messages when they come through, and I actually met up with one of them at a house party he was invited to.
When I forwarded the invitation, he suggested coming along as well and I figured why the hell not. It was a fun ice breaker in a room full of strangers.
But in the last few years I started getting hotel reservations, golf course membership, bills, orders for liver supplements. I tracked down who it is ages ago and sent them an email (I was cordial - "Hey we have such similar names but I'm on the other side of the world, crazy huh?") and got no response. Eventually I replied to the liver pill people and said "Hey this isn't me and if you could let the actual person know that'd be great" and the emails stopped. Way to go liver pill people.