I had similar ticketing experience 3 weeks ago but it was with CO where I found cheaper tickets online while the agent could not see the price even with the identical routing and fare buckets. I believe that I was transferred to the internet or customer support. CO agent did not call me a liar though, as he was able to see what I saw after requesting me to start over again and book till the credit card step. However, he was still unable to get that fare for me and he had to type and change the fare rule on his end in order to get me the same deal. The overall process took over 30 min and I thought I was unlucky, but hearing your case......wow.