Complain againt builder on illegal construction

I have booked a flat and have paid two third of the amount. Partially by loan and partially paid by me. The construction is about to complete, but I saw that the builder has provided additional gate in the flat adjacent to my flat . This gate was not in the plan and now the new gate of my neighbor is facing directly my entrance. I am being uncomfortable due to this as it is breaching my privacy. I had told the builder repeatedly to close that gate but he is refusing to do that. The flat which i have bought is really a good one and since i was among the initial buyers so got it at a very low price. Just due to this i dont want to cancel my registration. But I want to teach build a lesson. I read the RERA Act 2016 Section 14 and it says that builder cannot make any change in the layout plan and in this case its an additional entrance to my neighbor. So what will be the right time to complain against the builder as i want to purchase that flat ? Will it be fine to file a RERA complain against the builder after I purchase it ? And what could be the possible settlements of this case ?