I purchased a y class ticket and 1 segment is still waiting for upgrade. Flight is in 2 days. I am platinum as well. Seat map shows 1 first class seat available but reservation and customer service says there is no first class seat available(sold out). This is also happening often on many flights where the seat map in coach is not showing availability but when I get on the flight the flight is fairly empty. What is the reasoning for the seat map not being correct?