I dunno. I emailed someone who stiffed me on a bitcoin trade back in the day. I sent him $7 via PayPal and he was supposed to send me 100 bitcoins.
He never did. I told him I’m sure it was just an oversight and gave him an updated address to deliver the bitcoins to. I sometimes check the address to see if anything shows up, but no dice.
The email didn’t bounce though. So ya never know.