Originally Posted by Often1

The agent is correct, the refund is zero based on fare difference. What you could have done is obtained a full refund by stating that this was a trip in vain and asking to be returned to HOU and having your ticket cancelled.

The miles would have been returned to their original account (you said that your aunt paid so the miles go back to your aunt, not you). You would have been issued a BP for a flight back to HOU, you skip that flight and just drive on to TYS as you did.

But, I don't think that you can now say that the trip was in vain and that you want a refund. You can try, but I suspect that DL will correctly deny the request as you did not ask to return to HOU, so where did you go?

The 5K points were not a refund, but rather a customer service gesture.

I would leave well enough at this point as you run the risk of coming out with nothing and having DL treat the whole thing as, if not a fraud, an attempt to manipulate the SM system and that's not a good place because DL can simply boot you out of SM.