For an award ticket, there is no difference in fare between what you paid and how you travelled , so would not expect much of a response
I don't know how it could have been handled better, other than denying you boarding on that flight which you arrived late for and working to get adjacent seats on the next , given that it seems that getting you out despite being late at the gate was unsatisfactory
If you had made it clear that travelling together was necessary, I expect that you would not have been loaded onto the flight