I thought I'd chime in here since I too have had this happen to me. Earlier this year I was booked Basic Economy on SFO > SAN and UA had a schedule change of well over an hour that would've made my trip be in vain and violated their CoC qualifying me for a refund. Called Expedia (where I booked the ticket) who then spoke to UA and issued a refund request. Fast forward a week later and I receive an email from UA saying my flight could not be refunded because it's Basic Economy (absolute poppycock). This time I call the Premier Service desk and speak to someone there directly, explain the situation again and then have them agree to issue me a refund. A couple weeks later I see UA finally refunded me the fare I paid.

Talk about a runaround!

Safe Travels,

James