Can RWA Make Rules Asking Corpus Fund In Flat Resale

Hello community, I am buying a flat in a society in resale and RWA informed me about corpus fund that I have to pay. They showed me documents where in AGM members passed this rule of depositing 1 lack corpus fund from purchaser only. They are giving receipt of it as well. Can RWA make such rules? Do I have to pay? Is it legal?