Builder denying the parking space as agreed on before

Self has purchased a flat with covered parking area, for which no.mentioned in agreement. Builder shared parking plan with numbering before reg. through mail and confirm my PS. Since PS are of different sizes there is argument between owners for PS. Builder not shared their PS to other owners.Physical numbering also pending Now other owners and Builders are going for PS alloc.On lottery basis , but I strongly objected by siting reason slot for me already confirmed by builder by written commun. my stand is correct?. I am occupying larger sq.ft flat in that apt. i demanded fla sg.ft basis