If you don't get any satisfaction from the seller, and are stuck with the Cilt, it would make a good DIY project.
Armed with The Art Of Kiltmaking and some scraps of canvas it wouldn't be difficult to open the lining and install proper canvas lining and the stabiliser.
Yes a kilt without such will just keep on stretching! I've seen kilts that look terrible due to not having a stabiliser.
Proud Mountaineer from the Highlands of West Virginia; son of the Revolution and Civil War; first Europeans on the Guyandotte