This is going to be a really technical question regarding fare basis and a saga of refund issue, so please bear with me through the details.

I booked a ticket in the QA00A0RA fare class under the assumption that it was refundable/changeable (based on what my corp travel agency, Amex, told me). I ended up not taking the flight due to a weather delay and called the next day to get my refund. Amex tells me ticket is in DL's hands due to a reissue and to call them for a refund. I call DL and they tell me ticket is nonrefundable.

I contact our internal travel people to have them sort it out and get a refund. They got back to me yesterday saying that DL was incorrect and that a refund is now being processed. I headed over to expertflyer to check out the fare rules again and the only Q fare I found that was marketed on that date was QA00A0UA -- only one letter different than what I booked. This fare does indeed have a change penalty and is nonrefundable. I'm not sure what the actual rules were on the fare my ticket was booked on (ending in RA)

I'm wondering where the mistake happened -- did the DL rep pull up the wrong fare class (UA v RA)? For that matter, how can I find the fare rules for the RA fare? Finally, is there some glossary available to determining a DL fare basis breakdown?

Whenever we look at the e-ticket it tells the agent if it is refundable or not.

Right, so my question is what happened? DL says it's not refundable, but when Amex goes and looks into it it suddenly is refundable? FWIW the DL agent had me on hold for quite a while and quoted the fare rules to me when I tried the first time around, so I'm pretty sure she had the exact itin and fare rules open

I don't know if the fact it was bought via a travel agent changes things either. I bought a ticket via a web site travel agent who told me up front that the ticket carried a $250 cancellation fee. When I looked up the ticket on the Northwest site it stated non-refundable. When I wanted to cancel the ticket I had to go through the travel agent to get a refund as Northwest (delta -- this was in Dec.) was telling me the ticket was non-refundable.

Maybe your corp travel agency has a negotiated agreement with Delta?

...or it was a bulk ticket.