What would you do..............?

It is not your fault. You Simply made the mistake a lot of first time pet owners make. She is simply one of those back yard breeder people. It doesn't matter how much she paid for her Bengal if it is in poor condition and animals were not bred properly. You should check your state laws. In Florida, it is illegal to adopt out any animal younger than eight weeks, or without first shots and a health check certificate from a veterinarian. I would look up your state laws, and call animal control. You can ask them about laws, etc, and what are your rights. Regardless, that kitten should have been wormed and given first shots before being adopted out. In many states she can get in trouble for breeding and selling without a proper license. As far as the check bouncing.. did it bounce? Did you ask your bank? I am not sure. I agree you should not have been charged that without the kitten having health check, worming, and vaccinations, but at the same time you did write a check and you did accept that as payment. My best advice would be to call your local Animal Control and turn her in.