Refund Request Update: Refund finally processed! My CC account shows that the refund was processed on the day after my call, but did not post to my CC until 4 days later.
So, for those playing at home:
Refund Request Submitted: 12-March
Refund Request Processed: 10-May
Refund Credit on CC Acct.: 14-May (9 weeks from submission date)