Removal of secretary of housing co-op socy

Thanks a lot for providing this forum. 

I wish to know that the Secretary of the Housing Co-op Socy (based in Nagpur, Maharashtra) refuses to accept the resignation orders passed by the Executive body. He says that the Executive board doesnt have the authority to sack/ remove him from the post. I wish to understand if this is true and if yes, what is the correct way to relieve the secretary of his services before the expiry of his tenure.

Thanks.