If it hasn’t been done already, I would call the USPS 800 number (1-800-ASK-USPS) and speak with a CS rep about it (have your DC number ready). They have more tracking info available to them then they make available through the website or the tracking IVR. Sometimes they can tell if something looks wrong from their end.
Ask them for advice to see if they can figure out who you need to speak with about it.