It may very well do, when their staff numbers are down. In almost all airlines worldwide - and I don't see why FI would be much different - there are fewer customer service agents available than in "normal" times, frequently working from home (where, for various reasons, access to customer payment details may not be possible).

This smaller workforce would therefore already be behind if just trying to process the usual caseload of refund requests - but instead, they literally have to process almost every ticket issued for almost every flight originally scheduled to operate from mid March to the present date, and for all flights that had originally been scheduled for some time going forward...