It would be one thing had she not ignored you but that seals the deal for me.

If you wanted to be extra safe, you could also try mailing it to the address they just vacated and hope that they have their mail forwarded to their correct address.But at this point, I would just do exactly what @Dawn Anastasi suggested and keep the returned envelope still sealed with the check inside, along with the email documentation of your attempts to contact them, and let it go until they contact you.  

He's sitting sideways and breaking the way seal!

I had the technician look at what we need to do to seal the house from the rats, and at this point it is beyond our scope of work.

Mold always has a water source, and when it's on windows and by walls, it's the windows causing condensation because they aren't making a good enough seal.

I plan to go remove the bat and seal up any possible points of entry.

Somehow it malfunctioned, which I also agree shouldn't have been able to happen if it was bolted and sealed properly.  

If they were installed well and were a bit more modern we would probably be keeping them, but as it is they are an eyesore to the tenants, very difficult to get clean at turnover, and are not sealed up very well.

@John FiastroGo with the hardwoods it will reduce your ongoing costs.We do a light buff and then put several poly coats to seal the floors against liquids (beer, urine, juice etc.)Another great product is vinyl allure flooring.

If you're worried about water, aside from buying non-pressboard vanities, you can also seal the exposed edges of the vanity with a polyurethane (learned this trick from countertop installers who do it underneath the counter where the dishwasher and sink go), set it on a waterproof base/pedestal, or just replace it when it starts to warp and rot.