completely bald!!

Hey guys, so i have a serious problem here. I just put on new tires 2 months ago, and looked at them recently. The back tires are completely bald but the front ones are ok. What the heck is up with that??? I took it to where i got the tires and they told me that the rear camber cannot be adjusted like the front. They said that i either need a camber bolt, or a shim. What the f' is goin on here? They aligned my car when i got my S-techs installed, and then they re-aligned it and the difference is major. Did they give me a bad alignment the first time or what is this business about a camber bolt? Do any of you have camber bolts, or what did you do for this problem? I have a bad feeling that i am the only one in this forum that this has happened to and now i am very sad, pissed, and confused:confused: