Reset facebook privacy settings?

[anon]

I have so much trouble with facebook. first of all, i had my wall privacy set to "only me" for a little while before the new privacy settings were introduced just recently, and now when i try to enable my wall again all my old posts and comments, app posts etc. wont show to anybody but myself even if i set them to "friends" or "global/everyone". Only posts made by myself and others AFTER the new privacy settings came are visible to everyone. Is there any way to reset my wall privacy settings so i can show all my old posts from friends, apps/game posts, photos im tagged in(on wall), comment activity, etc.? Second, i changed my username for the second time and i really need to remove it. i was stupid because i always thought i wouldn't use facebook anymore but now i really need it, and the username is not something i can keep till i get to college/work etc. I really cant make a new one either(dont ask why). ive heard of one case where someone got it changed back/removed by contacting facebook, but i cant figure out how. im actually willing to pay them to fix it. is there any way to call them or anything?