Deviation in Plan / Common Area Access

Sir/s This is a unique problem. There are two different buildings. Building A & Building B. Building A has a separate plan and the entrance is separate as per the approved plan. Likewise Building B has a separate plan and entrance. One Single builder has constructed both the buildings A and B and named it as "Ponni Flats - Block A and Block B. But as per approved plan both are different building with different parking space and different entrance. Building A is totally deviated from the approved plan. Now the Building A residents are using Building B passage and parking. Can this be considered as "Trespass" ? As it is named as Ponni Flats, people of Building A hold couple of meetings and incur nuisance to Building B people. The is NO association registered. In the Sale Deed of building A, they have mentioned the common areas of building B, to be accessed by the resident of building A. But as per approved plan, both are separate building and has separate plans. Is the Sale Deed Valid. There is no mention of "Flat/Apartment" anywhere in Sale Deed. Which has precedence. Sale Deed or Approved Plan ? Can we restrict Building A people to access the common area/entrance of Building B Can we mention it as "Trespass" and build a wall in between both the buildings ? Should be a Flat Name be registered (Should "Ponni Flats" name to be registered) The builder is also not a registered builder