Car Parking Issue

I purchased new Ready to Move 1 BHK flat in 2017 with open Car parking from builder . My car parking was similar in size like other open car parking (16 feet length*6 feet width)(96 square feet) however there was addition space of 3 feet after my parking space, which was vacant till May -2021,month end. Post that there is wall of used water filter plant. Now builder has built DISEL Generator plant concrete base which using 3 feet vacant land along with 2 feet of my parking space. When I asked to him that you are using my parking space he said , you already have the space of 96 squar foot which mention in sale agreement even after he use my 2 feet . He is now majoring my parking as 14 feet in length and 7.4 feet as width.He is now using tree plantation space of 1.4 feet addition in width to cover my 96 square feet area. Now after 3.5 years he is doing this and he said it was in the plan but while selling this parking space he never told me that my parking space area would be affected in future by DG set installation. In sale agreement he just mention 9.24 Square Meter as parking space but he did not mention dimensions. Earlier DG set was in his vacant land which he now using to bulit new construction site, hence he moved his DG set to 3 feet vacant + 2 feet of my parking space. Please suggest how can I fight with this and get justice.