So, finally these parents won and they've made their nest in my balcony. They've laid eggs and the eggs have hatched already. I couldn't follow up coz I have to climb over my window to enter the bedroom balcony. Jeetu mentioned them in his post 'Pigeon And My Money Plant'. I didn't want them to lay eggs here coz now they'll keep coming back, and these birds make a mess of the place where they live.
I'll try to show you pictures of the baby pigeons.