If you purchased your tickets through Air France, then I could potentially understand this delay in receiving your refund.

If you purchased your tickets through Delta, using a “normal” payment method (such as simply just using a credit card, and not combining in gift cards or credits) then I don’t see any reason why a regular agent shouldn’t be able to push this through immediately. About a month ago I canceled the last of my trips that I knew would be impossible due to COVID. One involved Korean Air (booked through Delta). A simple call and my refund was back to Amex in 2 or 3 days.

So, if booked through Delta, I would follow back up and ask if this refund can be processed manually, and if not, what is the reason?