If I were you I'd print out the United webpage, which says:

Earning miles - Singapore Airlines:

Earn Mileage Plus® miles on Singapore Airlines, serving 68 destinations in 39 countries. Singapore Airlines is one of 15 globe-spanning members of the Star Alliance™ network. Present your Mileage Plus number when making reservations and you can earn:


Economy Class—100% of actual miles flown
Business Class—125% of actual miles flown
First Class—150% of actual miles flown

http://www.ual.com/site/primary/1,10017,1193,00.html


And mail that along with a polite letter to MP explaining there are no exclusions to their own web page re classes required to be booked in, and that is what you relied upon before booking the tickets. Depending on your MP status I think they'll see your point. Good luck.




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~ Glen ~