You should hold up your end of a contract even if the other party does not. Then you have a leg to stand on. In this kind of situation the sane advice has to be to continue behaving professionally even if they are not.
That's true. However while they're flagrantly in breach of contract I don't know what the right thing to do is. I also hope (although I have no illusions) that it'd be reasonable to not pay rent while they do something ridiculous such as not maintain the property.
I'm pretty sure tenants have no such right, and there's no remedy available for bad landlords... but I might as well ask

