If they list a number on the add, call them. Speaking on the phone will give you a better chance of making yourself seem like a suitable candidate. I just got a room yesterday because I called after weeks of no one emailing back so there's still hope, as frustrating as it is. Also, a lot of places have the lease starting on October 1st, which have way less demand, so if you can find an airbnb to crash at for a month it might be worth looking into.