Co-operative housing society membership.

My uncle purchased a flat of a co-operative housing society and he is the member of that society. he was a bachelor and nominated me in respect of the said flat as his only nominee under West Bengal Co-operative societies act, 1983. My said uncle died in the year 2007. Thereafter i have applied to the secretary for membership of the society as a nominee on 05/01/2013 but he refused to accept my letter and then i have approached to the Registrar of the Co-operative society. But still now i did not get any response from his end. What should i do for getting membership of the co-operative housing society ?