Unpermitted Pets on Premises

[Brent Mosser]

First time property owner in Indiana.

Tenants are 9 months into their lease. 

First issue is cats, lease states no cats permitted on the premises. Air conditioning went out 7/10 and the house was entered by myself on 7/11. Upon entering  the home I was immediately smacked in the face by the smell of ammonia, and I watched a cat enter through the screen of the storm door (torn up by cats and/or their dogs). What action can I take as a landlord besides a non-renewal? This will be served Oct 1, 2020 with tenants having to vacate by Nov 1,2020. 

2nd issue, Our HVAC guy recommended not replacing the AC/ Furnace until tenants vacate to help with clearing out the smell first. Tenants have window AC as well as we have offered to provide them if needed as well. I've been told that according to Indiana law AC does not have to be provided, but then I've read on a few forums where if it is available with the start of lease that the landlord is responsible for keeping it "running"

All recommendations will be greatly appreciated!