Does SSA Lose Documents?

While I was speaking with someone over the phone today, I was asked the following question: "How reliable is the Social Security Administration when it comes to processing Social Security disability claims, I mean, do they ever lose documents?"

Like the picture worth a thousand words, I had too many words that I wanted to say and my response came out completely jumbled. To clarify, I told the individual it might be easier for me to write about it tonight with examples, here they are!

Scenario 1: Several weeks back I sent records to SSA via mail and fax, they claim to have never received the records.

Scenario 2: I sent records certified mail to a District Office and called for the status of the records, they claim it never got to their office.

Scenario 3: I walk a document into a District Office personally, several weeks later when I called for the status of said document, it is no where to be found.

-Each of these scenarios have happened to me on numerous occasions. I have learned, often the hard way, not to assume that something is received by SSA just because you sent it. Keeping copies of everything is very important. Also, it is a good idea to send important documents to SSA multiple times.