Similar situation here. I had an ATL-LAX segment removed from my history that I flew. When I entered the ticket number to request mileage credit, I see that the segment shows up as refunded (!?!?) even though it has the correct class purchased/flown codes.
I sent a note to "Contact Us" about the issue a few days ago. No response yet.
The weird thing was the flight posted correctly after I flew it. Then after two weeks, it just disappeared. (My first segment of the day to ATL posted correctly and is still there.)