we have Rimowa trunks and clam cases for over 5 years now. Many miles on all of them and have seen scuffs, dings and pressure marks from stacking but never have heard or seen a crack.
We did lose a wheel cap once in NY and the Luggage store arranged for a replacement to be sent to out home. After a week we recieved the whole wheel assembly
.
I would contact them.
And chastise the airline that did this !!