I have a issue with the parking lot allotted.

Dear Sir, Our flat consist of 5 Flats and I purchased a flat in chennai in April 2010 and I was the first person to register the flat. During that time the drawings given to me showed 4 parking. There was one flat which was not soled for nearly 3 years and after which it was sold. During that time an representative drew a different line and made the 4 parking to 5. During this the parking lot allotted to me (No marking of any flat numbers in any of the parking lot) have a beam and it is wasting around 3 - 4 feet of space. It was not notified to anyone and no written permission was obtained during this remarking. All these while I didn't had a car and now I purchased a car. I am facing the difficulty of parking as there are 4 cars now. I wanted to resolve this issue with the builder and I was speaking to him but he said after such a long period you are asking and he cannot do anything and disconnected the call. Plan approval drawing have only 3 car parking. Can I proceed with legal proceeding now as I have purchased it in April 2010? Need your valuable suggestion how I can approach this situation. Regards, V. Karthik