Sold my flat retaining my covered parking.

I had purchased a flat in a co.operative housing society Navi Mumbai Nerul in 2007,and at the same time had also purchased a covered parking space from the builder paying for both separately.I have registered documents for the same. Then i sold my flat in the year 2009 retaining my covered parking space as i had purchased it separately from the builder before the society was formed.At the time of selling my flat the society gave Noc and transfered the flat in the buyers name.Now after so many years the society is forcing me to hand over my private parking to the society as I hold no shares in the society.They say I am no longer a member of the society as i have sold my flat, the parking does not belong to me. Please do guide me, My parking is not a common parking nor a stilt one.It is covered from all four sides.Isn't a parking space which is covered from all four sides (a roof, walls on all three sides,shutter in front)said to be a"flat" according to MOFA Act Section(a-1)?Can't I retain my covered parking space if i don't own a flat in the society?Is there any problem if i don't have shares in the society? Should I apply for a membership?What should I do to use it legally?