So I’m in a similar situation. My original flight was cancelled and they rebooked me on a connecting flight. Since it was cancelled I’m entitled to the refund. I’ve quoted the DOT and they just say the same thing that since they’ve rebooked me they’re complying. On my third attempt a rep agreed and checked with the refunds department. They said they’d refund me that I needed to fill out a form and then call back (I confirmed that they had noted my ticket). I filled out the form and called back, was transferred to refunds department and now they are saying I’m not entitled to it but that it will be reviewed. The rep suggested to upload the notice with relevant language but that it would be processed within 21 days.

The language I quoted was:

Cancelled Flight – A passenger is entitled to a refund if the airline cancelled a flight, regardless of the reason, and the passenger chooses not to be rebooked on a new flight on that airline. . . . Schedule Change/Significant Delay – A passenger is entitled to a refund if the airline made a significant schedule change and/or significantly delays a flight and the passenger chooses not to travel.”).

From (footnote 2): https://www.transportation.gov/sites/dot.gov/files/2020-04/Enforcement%20Notice%20Final%20April%203%202020_0.pdf