Can a person buy a flat from housing society

My landlord is trying to evict me using land grabbing act.

He says he bought the flat from my housing society by purchasing 5 shares of Rs 100/- each last year 2022.

He used those share certificate to register the property & got a copy of (7-12) from revenue records.He used that to enter his name in property tax records. He used those two documents to file an application under Land Grab act.

 (1) Housing society's name wasn't in property tax bills but someone else's ( I think Land Owner's ) name & I have been paying those property tax bills for last 16 years by checks.

(2) Society's name wasn't in (7-12) records as of last year & I have that copy.

(3) So how can society sell the flat by giving just 5 share certificate when they don't own the flat OR do they ?

(4) Why didn't they give him "Sales Deed" Or why didn't he ask for it ?

(5) Isn't Sales Deed a must document for all of above entries ?

Thank You