Builder shown different plan when selling the appartment.

Hello, My builder shown us one plan with 840 sqft carpet in Pune Location. We liked the design and finalized the apartment. At that time the building was completed till ~8 floor but they did not allow us to visit the site stating some rules that customer can't visit site when its under construction. Post 8 months of purchase we went to the office one day and asked for a site visit and they surprisingly allowed us. Then we found that they have made a change in plan for one of the room which is shifting 3 fts from its original location as shown in the plan. Though the carpet area is still the same at 840 sqft However, when I checked the agreement where it contains the plan approved by the authorities, its not the one they showed us when we purchased the apartment rather its the one which is being constructed. So in conclusion, the builder is building as per the sectioned plan but they have showed us a different plan. When I reached out to them about this issue they said it was a change during the implementation stage and did not knew about when selling it to us. Also I asked for compensation or the cancellation of the booking but they are not responding to any query other then excuses and ignorance. Can anyone suggest what are my legal options in this case ?