Sorry this happened to you, OP. Since you can’t post links yet, I will post the link to the Sherpa carriers for you.
Original Deluxe | Sherpa Pet
Just one small point - AC is not one of Sherpa’s “Guaranteed On Board” airlines. Not that it makes a difference in your case but just as a reference point. The medium Sherpa is only guaranteed on AA and UA.
The Sherpa™ Medium Original Deluxe™ Carrier is Guaranteed on Board® on the below airlines.
American Airlines United Airlines