I need help with problematic tenants

[Liz Lozano]

I own 3 units, have tenants that have been living in one of the units for no more then 3 months. They complained about Fleas. I hired pest control to go fumigate. Tenant called me back after a week complained about Fleas once again, I hired pest control once again and they told me that there wasn't any Fleas. Ok, well she then called me for the 3rd time telling me that if I don't resolved the problem she wasn't going to pay me the rent. I went out and bought all sorts of powders for Fleas, went underneath the unit, sprayed all the yard, did anything in my control. A few weeks pass by and she called me and said that she was moving out because the place was still infested and she has doctors letters and pictures of Fleas going inside her ears and mouth. So, she was going to call Health Department before she moves out. I have all receipts to prove that I did everything in my control, we change carpet. My other tenants have not complain what so ever and we also fumigated all units. I have no idea what to do any more. She also mention to me that she wasn't going to sue me because she lost her furniture and mattresses due to Fleas. Please help with advice. Thanks in advance