WeTransfer email received without ever using the service I'm am using a MacBook Pro 2012 using El Captain version 10.11.3

I received 5 minutes ago an email from WeTransfer (noreply@wetransfer.com) saying that "Your file has been sent to ***@libero.it. As soon as the recipient will have downloaded the file, you'll receive a confirmation email. Name of file: IMG_0508.mov", dimension: 30 MB", and there was a link to download. After 1 minute I received another email telling me that the file was indeed downloaded by the recipient.

The problem is that I never used WeTransfer, wasn't even aware of its existence 10 minutes ago! Apparently it's a legitimate service, which I never used. I don't know whose that email belong to (even though the email provider is well known in Italy) and I have no clue what is going on. Obviously I did not click on any link on the email, thinking it was just a scam mail that tries to make you click on the download button to install some malware.

But given that the company seems genuine, I'm worried that some hackers have somehow compromised my system and sent themselves a file with my stuff, and immediately downloading it (30 MB in one minute means the recipient is ready to receive the email). On the other hand I wonder why they would put my email address for me to receive such an email... 

I disabled the wifi of the Mac and I am writing this from my phone. I also started a full system scan with BitDefender virus scanner (don't know how helpful it is, but still. I do it once in a blue moon though, never found anything)

So what has happened? What do I do now to protect myself?

Edit

I received another email just now. Apparently this person just sent me back this file, and WeTransfer informs me that I can now download this. So to recap: 1st email is about me sending file A to person B, 2nd email one minute later is to tell me that person B downloaded file A, and finally 10 minutes later to tell me that person B has sent me file A.

P.S. having trouble adding tags from the phone
Or person C mistyped their email address and you're receiving their notifications.

Not at all unusual.