And you can see the SPS in there, rock solid, doing its job. The poor cake looks like it was held at an angle for quite some time (riding on a lap in the car). Then when they opened the box and found its backside smooshed all over the box, they tried to push it back to the center of the board, damaging it further.
Melvira is spot on with her advice - you basically have to write her back an email telling her how sorry you are that she destroyed the cake, without coming out and saying so.
By the way, extremely cute cake, I feel sorry for all parties involved that it met this fate.