Public Storage Sold $75,000 worth of property for $140, NEVER notified me of sale then took $500 payment from me Atlanta, Georgia

The schedule of fees and charges is the very first paragraph on the lease that you SIGNED. The first page ALSO explains the lien and auction process in your state. Are you in the habit of signing things without reading and comprehending them?...I guess so

I hated how every one whose unit is sold complains about how P.S. sold their stuff legally when they should be complaining about how awful the laws are that allow P.S. to sell your stuff. Under Georgia law P.S. has a lien on your goods once you are 10 days late, that's right TEN DAYS. Then once you become TEN days late you stay in lien until you pay in FULL. They can sell your stuff if you stay in lien for 30 days. Meaning literally If your rent is due on December first and you figure hey I have a ten day grace period and put your check in the mail on the 9th, but it does not make it there until the 11th. Now you did not include your late fee because you expected if to arrive on time. I mean come on the envelope is postmarked; but the contract explicitly states the payment must be RECEIVED not mailed by the tenth. This means your goods are still in lien 30 days later would mean P.S. can LEGALLY sell your goods on January 10th.
 All the while you think you are still in the grace period. You might think you are fine because you did not receive any notice about the auction. THIS IS ALSO LEGAL. According to Georgia law P.S. must notify you at your last known address. You might think incorrectly that the return address on your payment or the new address on your check would tell them you moved, even you telling them over the phone doe NOT constitute a change of address. It does not. According to Georgia law "Last known address" means that address provided by the occupant in the latest rental agreement". GA  10-4-210. Short title. All the while P.S. All the while P.S. pays NO TAXES. They are a real estate investment trust meaning they pay $0 in taxes as long as they distribute 90% of their taxable income to their billionaire investors like B. Wayne Hughes. 
You may want the buyers to know your sob story but I can guarantee you they do not care. I worked with them for more than 7 years and a lot of them are vultures. One time I begged a buyer to sell the unit he just bought at auction 10 minutes after he bought it. She was a widow with two small children. She owed less than $150. It was the current's month rent and the previous month's late/lien fees. She thought she was current she owed the only some fees she was unaware of and that months rent. Her husband was in the service and died overseas. She came in to pay the day of the auction and missed it by 10 minutes. I begged him to sell the stuff back to the WAR WIDOW. She owed less than $150. He bought it for $700. He would only return it for $1400 cash that day. He had not even been inside of the unit. He had not invested 10 minutes of his time. He had not opened one box, but he made that poor woman pay ten times what she owed. 
When I shared what happened at another auction the other bidders called him a fool and said they always charge a 300% markup. Trust me they bid on the importunity to profit off your misfortune. P.S. requires the bidders to sign a "sign in sheet" that says they will return personal documents but less than half the buyers do.    

I am sorry about your loss, but they probably were totally legal in what they did.   Your only "out" would require you looking at the Laws and seeing what they are required to do before an unit is sold.  If they can't prove they did what was required you may have a claim.  However, remember they may only be required to send a letter to the last known address.  Which makes some of your comments quite pertinent.

Twp weeks after my move, and four days prior to moving into my new home, a devastating tornado hit the area and rendered me homeless.
- What about insurance?  You had over 75K in storage so one would figure that you could afford insurance that would have covered temporary housing.

I stayed in CONSTANT contact with Public Storage regarding my possessions,
- Not exactly.  You were in constant contact from April to July.  After July the next thing you mention is finding out in September that your stuff was sold.

I never received any notice of pending sale, which I would have NEVER let happen.
- Interesting how the items were sold about the same time you stopped contacting them.  Also if you would NEVER have let it happened what would you have done?  Would you have found a way to get your bill current?  If so then why didn't you do that anyways?

I want to get a court order compelling them to tell the buyers my property was sold without my knowledge and requiring them to tell me where my things are and how I can get back my personal papers, and family heirlooms.
- Even if they told you who bought the units(which won't happen) they are not going compel those people to return what ever items they have.  In fact as much as you don't want to hear this but unless your items have some sort of monetary value they are long gone.