Choster,
Wow! The DM card thing and reply from res must've really pushed your buttons! (It would have made me flip my lid) Unfortunately, res (at least back then) had no access to the airport checkin system to see that you were on the DM list. Instead of being so terse, they (if they couldn't confirm or deny that you had checked in) should have at the LEAST have bumped you up the red-tape ladder to customer relations the next day (assuming they were closed at this time) where they could see the checkin history.
I'm glad that you didn't accept their initial lack of knowledge at face value (how could you?!?) and give up there.
Long story short...the CS agent was most likely only "gate qualified" and didn't have much skill at ticketing/refunds. Brushing you off was weak. I can see them try to help the masses with what they could, instead of delaying them all in a vain attempt at processing a refund that they (he/she) were not qualified to do. UAX agents were never trained in any ticketing transactions as a rule of thumb, (UA has been trying to change this, and has improved in this area greatly) and sent people to the UA counters at the hubs for refunds.
Beyond a whole refund for a completely unused ticket, whatever UA were to do for you would be pure "good will". Once you turn that ticket in for a refund, you also turn in your link to anything the contract of carriage entitles you to. No ticket=no rights.
It stinks that an airline's (UA's or anyones for that matters) contracts have no provisions or liability for failing to operate a schedule...I guess if they did, prices would have to increase to cover the additional liability.