Unfortunately you have to continue to pay the full amount of rent. Keep hassling at the agency daily by phone and email if you can. It's pretty much all you can do at this point. Let them know how annoyed you are too. At $520 a week the landlord should be able to repair the air con! It takes one phone call to find out if it's covered under warranty and arrange a repair. You can always ask for a rent reduction until it's repaired and see how you go..

I feel for you this heat is hideous.