Thank you for reply.
About explanation of "speed and diligence" is exactly words from letter to me sent by TIAA-CREF, and also is the official explaination for my case.
I thought my money was moved, for when I called them in the beginning, an agent told me I had money withdrew. But I didn't.
Second, the balance in my tax form is not right. But when they changed my balance on Jan, they didn't give me a right explaination. After I found my account problem, my quarter balance is not available online all the time.
Sorry for my poor english, my chinese typing is too bad.