Help! Tenants refusing to shut off leaking a/c

[Lindsay Repp]

Hey guys, 

I have some tenants who have been giving me problems since they moved in, and just recently have notified me that the ac (located above the master closet ) is leaking into the closet ceiling. I promptly gave them the number to my ac guy to schedule an appt. They call me a day later saying the leak is getting worse and it is so hot outside it is "impossible" to turn the ac off. The ac guy is supposed to come out in 4 days and they said since ac is in their lease they will not be turning the ac off. Is my only option to let them damage the unit and take it from security deposit after they move out? Or am I legally able to shut the unit off from the outside since they expressed the intent to be negligent.. 

Thanks for any and all advice!!

Lindsay