Refund issues

I ordered food online, after a whole 20 minutes of waiting for the store to accept, my order gets declined and I get a pop up which reads "we have refunded you immediately". I then camled my bank to query the transaction and am advised that the funds are on hold by Mr D. Again I call Mr D and after being transferred from pillar to post I simply get told "Sorry man the refunds takes 3 to 7 days to process"

This is utter nonsense!