Call Delta Cooperate Customer Care
about post travel complaint
tell them about the bag fees and tell them they have to refund you portion of the flight because of the downgrade due to the delay.

Refund department should email you and ask for your receipt or situation, send them the receipt and/or credit card statement and they should send you a cheque.

They refunded me and my companion lounge fee before because of the closure of the shower in Moscow lounge. They have better flexibility on F tickets