Air India Express — did not get the front row seat even though paid for it.

We flew airindia express from calicut to al ain on 10th january 2019. We booked the front row seat but did not get it. We paid extra 790 per ticket but got the last row seat. I would like to get the money back please.
We booked the front row seat because we are elderly people who need some convenience during flight. Its very unfair that we pay for the front row seat and somebody else sit on it!