It must be nerve wracking waiting for your luggage to arrive. The weather earlier this week disrupted transportation in many parts of the country. It does seem to be back on track now on the Osaka-Tokyo route. As for the Japan Post delivering your luggage, did you have it sent expedited? If so, then it should be there by Friday even though it wasn't stipulated when you sent it.
More phone calls from your hotel in Narita might help expedite things.
Good luck!