I just experienced a different version of this. Booked a return flight VIE-FCO through Delta (006 ticket stock) on Alitalia. I booked an economy flight, but it shows up as "F". I thought I got lucky and was somehow mysteriously upgraded to first class (although I doubt there is a first class on a 1 hour intra-Europe flight). The boarding pass shows "Y" class. A couple of days later the flight shows up on delta.com with zero miles and "non eligible" marker. I call Delta and they tell me that "F" class is not eligible for milage. Looking up the miles earning chart for Alitalia flights, indeed "F" is not listed. Cheap .......s, now I am 311 miles short on renewing my status for 2016.