I had a mold issue years ago when I was living in Indianapolis. Mold began showing up under my cat's litter box. I still highly doubt it was the litter box as she never peed on the carpet - I think it was a mixture of a leak under the carpet plus the mat under the box holding the moisture in. In any case, they never made any noise about the cat because I paid my dues for her every month, per my lease agreement, and they fixed the problem with a small deductible from me (again, per my lease).
Read over your lease agreement carefully and see what your rights are in this situation. In my experience, good apartment complexes don't make demands that are outside of their agreements, and if they do, they back off quickly when you pull out the lease. If you have a signed lease agreement and they still aren't abiding by it, that's the time to go to a lawyer.
If you don't have any agreement signed between you and the owners, you're most likely out of luck... going to a lawyer will only make things way more expensive for you. And you'll probably have to vacate before anything gets done anyway.