is it possible the application been lost?

My hu*****and filed the I130 for his siblings on 11/26/2007 to Vermont service center. But so far, we haven't received the receipt or other notification, the checks still haven't been cashed.

Is this normal, I came here first to get something clue before calling them. I mailed priority with deliver confirmation, the delivery status showed delivered.

I don't know what's the process for filing GC for siblings.

I do know it will take a long time for sibling's GC process. But I am not sure whether or not it will also take a long time to get the receipt( make sure they really received it, and under waiting list).

I just want to make sure the application won't get lost.

Thanks someone's inputs.