When you first filed the 751 you got a NOA that serves as your extension. I am assuming you entered the case number from it into the online system and also used that case number to fill out the ar11 right? The biometrics appointment letter can have a different case number. In the past people were sometimes unable to use the NOA from the extension to see the case status and needed to enter the one from the biometrics notice.
Is there a different # on the biometrics than the extension?
I was speaking to tier2 officer and she told me she'll send a copy to my email right away.
Try to request call back again, they not always call back from the first try.