Ownerhip and occupance of car parking space by the promoter as his office area

We purchased a flat in trichy, Tamilnadu in June2017 in 3rd floor whereas the apartment is 4 floors with stilt car parking. The apartment has a complex in front. the land owner has given the power to the builder for construction and sale of flats. The initial approval was got from Trichy corporation for the construction of both complex and residential flats together with common basement parking. But the complex was first built with basement car parking, later on residential construction was initiated by giving the power to the builder. The initial approval has a different plan for the flats while the built ones are different. The inital approval has common basement parking for both complex and residential area with a small office room in the basement. But the built ones are different. 5 houses were given to the land owners but only 3 parking spaces were given to them. And 2 house owners dint require car parking. Now the same 4 spaces has been occupied and registered in the builder's name as office area and he is claiming to conduct a small book shop and his builder office in that area. This registration was not done with the consent of any of the house owners. When asked during the construction stages, that space was said as godown for construction materials. Kindly help us in this issue.