A: This depends. If the hamsters are not being given access to food and water at all times, or if their cage/container is unsanitary (or any other immediate need for alarm)- then by all means- contact a manager- then follow up about 24 hours later to see if they have fixed the problem. If they have, it's still a good idea to check back several more times to make sure they are "sticking with it." But if the problem continues, please contact your local aspca, or click here: www.aspca.org
On the other hand, if it's that they are not meeting the hamster's "wild" needs, as addressed in this site, I can offer a solution that may or may not make a difference.
Some store managers will listen to suggestions- some do not care. Unfortunately, most stores will only be equipped/trained to handle the very minimum, basic physical needs- if that. Many will not even invest the ten dollars or less to make sure each cage/container provides a wheel- which I personally feel is emotional and physical abuse (if it is for more than a day or so at a time.) But being that it's just my opinion- I would have a hard time convincing any animal "authorities" to take action for such a thing.
If you are able to get the store manager/owner to listen to suggestions, great! Tell them what you know about a hamster's basic "wild" needs, and please feel free to pass along SH's URL: www.oocities.org/spoiledhamsters/index.html