Air India — discrimination due to gender (sexism)

I was travelling from Bikaner to Delhi on 31st May 2018.
I have a knee problem and had been advised to keep my leg straight and therefore requested the ground staff (counter at Bikaner) to allocate the seat in the first row as it was unallocated. He said it won't be possible as you're a lady and won't be able to open the exit door! Firstly I wasn't requesting for the entire 1st row and was only requesting because the doctor had adviaed.
[protected] is my FF no. So have been on Air India quite a few times.
Also was travelling to Bikaner for the 3rd-4th time and never faced this problem but was totally disgusted by this attitude.! Hoping for a compensation at the earliest.