I spoke with OPM today (and recommend that you do too)
I am a 9/30 retiree whose file was received at OPM mid-January. I've been receiving 50% interim payments, but have seen no other movement with my case. Somewhat on a whim, I decided to call OPM today (2:30 on a Friday afternoon) and to my surprise was able to get into the hold queue. They said it would be "more than 10 minutes" and it took 45, but a live person eventually picked up the phone. She indicated it had not yet been assigned to a specialist, but able to confirm that there was no specific reason at this point for the delay in processing my case other than the general backlog and understaffing problems. Her assessment was that my case was taking a bit longer than average but not out of the ordinary (alas).
While this information unfortunately does not help my checking account balance, I am surprised by what a sense of relief I have felt since that call, and therefore wanted to post here to encourage others in a similar position to consider calling as well. My biggest concern has been that OPM had not received some piece of information it needed from my agency, and I would be sitting in limbo forever not knowing. At least I know that's not the reason for the holdup, and that I just need to wait my turn. (Even if others who retired after I did are for some reason getting processed ahead of me. Grrrrr).
In short, having a live human confirm that my case is in the queue for processing -- in what is now month 8 of my retirement -- was unexepctedly reassuring. The OPM specialist was extremely professional and candid, which I appreciated. I thanked her for her service, noting that hers must not be a very fun job these days. I'm glad to see more reports here of 9/30 retirees getting their cases finalized, and look forward to being able to report the same myself, someday.