Have they checked them for parasites? We had a problem with this awhile back and it took some time for them to get over it. They gave ours Flagyl and we fed them small amounts of food several times a day. Be sure they stay hydrated and maybe keep them secluded in a bathroom, spare room, until they're over this. We kept ours in the spare bath away from the other cats. Wish I could be of more help here. I can sure relate to the $$$.