I had a similar situation , my outbound flight was delayed by 9 hours, I got the same answer you did , back and forth between the vendor and carrier , I ended up disputing my charge with my credit card company , airlines apparently did not respond to my credit card company within 60 days of my dispute , I got all of my money back.Slight issue however , I received partial refund from the airlines , full refund from the credit card as well, leaving me with more than what I had paid, it took few months for credit card to make it right . It worked for me , not sure if it is the wisest way to do it though.