In another wrinkle, I just got an email from United referring to a complaint I
filed with the DOT about this issue:
I am sending this letter in response to the complaint forwarded to us by the Department of Transportation in regards to your travel on United Airlines.
I have contacted the MileagePlus department on your behalf and they have advised me that the miles posted to your account on yesterday 5/16/12.
So, maybe the 6 calls I made to United, the 5 calls I made to Air China, and the 3 times Air China called and emailed United didn't solve the problem, but the complaint I filed with the DOT did.
http://airconsumer.ost.dot.gov/CP_AirlineService.htm