Cool story and yay for rehoming the fishies!
This happened to me once, the vendor shipped someone elses order to me that had a pyramid butterfly fish, vs the sensibly sized fish I ordered. I posted on a couple of forums/facebook to rehome it, and it was adopted within minutes gratefully.
The woman on the phone when I called to report the error, said they received several calls that day of mismatched orders and someone apparently received a shark egg!

Yikes! I wouldn't want to be responsible for finding someone to rehome one of those because of their care requirements and it most certainly would not have survived more than a few days in my care/aquarium.