Hi Juanita,
It is a sad thing to encounter but unfortunately many (especially chain) pet stores are notorious for improper herp care. The fact that there are 3 chams in a 10-gallon tank the manager will soon have 3 dead chams.
This is a topic often visited on this forum and most of us will agree with Matt - as cruel as it may seem. By buying an animal from a store that does not have proper care you are condoning their sale - as Matt said, money is money. I rescued three anoles from a PetCo a couple years ago and eventually shipped them down to my Mom in FL to set them free. I realized afterwards that it may have made a difference to those 3 anoles but it made no difference to the store. The next time I was in there nothing had changed and the "reptile keeper" in charge got very defensive about my suggestions.
What you might try is to enlighten the storeowner by bringing in some care sheets and offering advice as an experienced cham keeper. If you feel the need to care for this cham offer to take it free (therefore they have now lost money) to try and nurse it back to health. Just be prepared for vet bills and a good chance of losing the cham. If the owner is not receptive to your help (changing things not necessarily the adoption) then I would go to the local animal humane society, herp society and/or local animal welfare department. It seems a drastic step but often has to be done - and that doesn't always do the trick either. We have a local pet store that has been reported several times but is still in business – it is sickening. If the store is not a chain store, you may have better luck developing a relationship with them.
There are stories of both success and failure from folks on this forum and it is heartbreaking each time simply due to the fact that the poor animal was subjected to this in the first place.
You are in WA, right? Here are links to your local societies.
lele
herp societies in WA
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0.1 veiled - Luna
0.2 felines - Kyndra and Líta
1.0 African Clawed Frog - Skipper
0.5 Mad. Hissers
0.1 Chilean Rose Hair Tarantula (no name yet)
?.? Goliath Bird-Eater Tarantula (no name yet)