Who do I complain to when the head person in charge is no help?

I live in this complex in Atl GA it is terrible and they over charge everyone for the water bill, I found out from the mail carrier that mail was no longer being delivered at the apts b/c it was being stolen and all resident would have to pick it up at the post office, the office never told anyone they did not even put up a sign to tell the residence this. The outside of every unit floods when it rains, and to top it off all the entry and exit gates have been broken since I have lived there which is about 5 months basically there is only one way in and out. I hate this complex and as expensive as it is a month there should be not as many problems. I complain to the istant manager in the leasing office she is ignorant and takes no one seriously, I main leasing manager looks like she is younger then me and has no clue what she is doing, I am 24 and the head property manager I wrote him several emails all he can do is say I am sorry but pls talk to the property manger who is not help. Where do I go from here? because it seems as all the management are idiots.