You need to read your contract to see what the facility's remedy is when someone falls behind on payment. If they are within their right to sell the contents there is no much you can do other than ask if they will let you get your passpart. You could try filing an Order To Show Cause in court to stop the sale or at least allow you to retrieve your ID but it would cost you more than what you owe.
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Dear Pound Ridge Property Owner:
New York State law provides an operator of a self storage facility powerful tools to ensure that the rent due for the use of the storage is paid. There is almost no wiggle room. Falling behind in rent allows the owner to begin the process to sell the stored property at auction. It is almost always less expensive for the property owner to pay the past rent as swiftly as possible than to secure an attorney to postpone the sale or to run around on his own to a court to try to obtain a stay.
Read the Lien Law here:
Read your contract and the statute. You have so much at risk (how you could put such important personal documents into a storage locker is another matter altogether) that if you have any friends or family, borrow now to avoid a horrible loss, and then figure out how you will go forward.
The answer provided to you is in the nature of general information. The general proposition being that you should try to avoid a bad outcome if you can.