I agree with that analysis of irishguy. I have had plenty of delays and missed flights or changes at the airport due to delays and have always checked with the airline and got some voucher or other document as proof before changing a flight or any other procedure. The plain fact here seems to be that you acted in haste with some verbal assurances. That is basically worthless. You have to go through the motions with the airline. Ie board the flight, get told there is a delay, get offerred compensation, take what is offered then escalate later. You decided you didn't have time for that which was a risk.