Builder raise the demand before millstone is completed

Hi, This is regarding unjustified demand for payment raised by builder. As per the construction linked payment plan, the milestones listed were: Booking Amount On Conrpletion of Excavation On Completion of Plinth On Completion of 2nd Floor On Completion of 8th Floor On Completion of 18th Floor On Completion of Superstructure On Completion of Tenace On Completion of Walls My flat was on 9th floor. Our understanding of Completion of walls - as confirmed while purchasing the flat and also confirmed by initial proposal to buy from builder - is this would be on completion of walls for whole Tower. Now the builder has raised this letter, demanding payment saying that the Completion of walls means completion of brickwork of your floor. Any legal action can be taken in this discrepancy They did put in a line at the end of construction linked plan that these demands can be raised irrespective or order. However, i still feel they should have mentioned On Completion of Payment of Brickwork for your floor.