Encroachment of a car park

I bought a flat from a developer and its cost included a covered car parking slot. While registering the construction agreement, the apartment’s plan and a plan of the car park was also registered. In the latter, a specific number was earmarked for the parking and the flat was handed over to me with these details. The flat remains unoccupied and, due to the pandemic, I did not visit it for the last year. When I recently paid a visit, I noticed that my car park has been converted into two areas that have been sold to a new owner. The site manager is offering me another car park which is not acceptable to me. How do I proceed? Can place a police complaint against the builder and the current occupier? Will TNRERA be helpful?

I am planning to buy a house in Noombal, Chennai. The total plot size is 1,400 sq.ft. and the builder has constructed two individual houses on this land. I plan to buy one of these houses (700 sq.ft.). As per the patta, the total land size is 1,076 sq. ft. but as per the latest Field Measurement Book (FMB) sketch, it measures 1,400 sq.ft. The builder says that if I were to purchase this house, the patta will be as per the latest FMB sketch. Do you suggest I go ahead with the deal? Will I get a patta for 700 sq.ft. or do I need to ask the builder to make the necessary changes in the current patta?