I've never had Refunds call me back, but I have once called the Refunds dept and chatted directly with a person who looped in a manager who could immediately resolve the issue.

(In my case the issue that UA had added the annotation NONREF during a date change to a refundable ticket; when I had later gone to refund it, Refunds had denied the request by e-mail, citing the bogus endorsement. I appealed to the actual fare rules of my ticket and got a supervisor to spot the issue and promise to fix it immediately, with a proper credit within a few days.)