Emirates Air Lines — Refund for seat reservation charges as emirates failed to provide reserved seats.

I booked mumbai dubai return ticket [booking ref - kdt77b] for travelling on 15th oct 22 with my family . I paid additional charges for reserving seat 22 h, j, k which was confirmed and tickets were issued with confirmed seats. When we checked in on 15th oct at mumbai airport we were alloted seat no 38 h, j, k in the tail section . When we questioned the counter staff informed that our reserved seats are not available due to change of aircraft . We asked them to call the supervisor but he refused to come and asked us to submit complaint to airlines . We lodged a complaint with emirates [ref dxb/x/ac/201022/7823696] but the airlines has refused to refund seat reservation charges saying that we were alloted 3 seats in the flight . I hereby request to help me in getting the refund for seat reservation charges as the airlines has failed to provide this paid service [reserved / confirmed seats ] due problem at their end. [change of aircraft ]