Indigo Airlines — Change of seat on flight without informing

I was travelling on 6E 5251 flight from Bangalore to Mumbai on 22nd August 2022.

I had paid and booked a seat 33 F . To my shock while boarding they inform my seat has been changed to 11 E which is a middle seat and not an aisle which was booked earlier

On checking with Inflight staff, I was rudely informed by Ms, Surai that she cannot do anythig and that flight is overbooked .

I mentioned have paid for aisle seat and the least they can do is give me an aisle.seat but she very rudely inforned nothing can be done now.

I wish to lodge an official complaint against the In flight staff for being rude and having no empathy, as well as the flight who has changed my seat against my consent.