BBMP not approving Building plan because they claim the BDA site is in buffer zone.

Hi Purchased a BDA site 2 years ago and now when I applied for building plan approval to BBMP they rejected the application stating that the site is in the lake buffer zone 30 meters from the lake. I have the following question. 1. First Question = The BDA layout was formed in the year 2004 before the drafting of the 2007 master plan which mandated a 30-meter buffer zone around lakes. this is quoted by BDA Chairmen (https://www.deccanherald.com/city/bengaluru-infrastructure/how-to-ditch-site-owners-a-step-by-step-guide-from-bda-1057693.html). so can BBMP apply these buffer zone rule to the layout that was formed 3 years before the buffer zone rule was drafted? 2. Second Question = The lake has a buffer zone of 15 meters around the lake which is fenced by BBMP. BBMP doesn't consider this 15 meters as the buffer zone. they consider this as part of the lake and they measure the distance of my site from the fence which is around the lake. is this correct? 3. ThirdQuestion = If the buffer zone rule is against me and I can't win against BBMP then can I ask the owner from whom I purchased the BDA site to cancel the sale deed and return my money? In the sale deed, there is a clause that was added that states that in case of any dispute the seller of the site will take complete responsibility and sort out the issue.