Not sending email to this address <removed>, but receiving a failed delivery notice

If you didn't send anything to that address, then delete the failure notice!
For all you know, it isn't even a real notice from the ISP, but a scam to get you to open it or try that email.
NEVER EVEN OPEN ANYTHING YOU AREN'T SURE OF!!

It's your run-of-the-mill spam/phishing email.

What is Phishing? Webopedia