I have Delta Platinum status. Wife and I returning to Salt Lake City from Africa on December 20, 2019, with First Class tickets. Final leg connecting flight is Toronto to Salt Lake. Arrived at Delta Sky Priority counter to request boarding passes for Toronto to Salt Lake flight, which departed one hour later. Delta agent denied both of us a board pass, claiming we arrived at his counter 7 minutes too late-now 53 minutes to scheduled departure. He would not rebook a later flight. I called Delta Help Line to rebook and was told nothing could be done because all Delta Flights to the United States are sold for December 20 and for December 21, 2019. I rebooked a return First Class flight from Toronto to Atlanta to Salt Lake by myself for that same day with my phone app. Each ticket cost $1,317.43, which is $848.40 more than my ticket from Toronto to Salt Lake ($469.03). I arrived at the boarding gate and see the flight from Toronto to Salt Lake is still boarding. Delta boarding agent won't let us board without boarding passes. On December 21, 2019, phoned Delta to request reimbursement of the two $1,317.43 tickets. Delta agent said claim should be approved and look for email from Delta. Six days later, my claim was denied by email by Delta because "these tickets were fully used." Delta agreed to refund only the cost of the two Toronto to Salt Lake tickets at $469.03 each, because "these tickets were not used". I used Delta Platinum AmEx for all bookings. I have filed a claim with AmEx. Thank you for you advise.