Hi! Thanks for the question!
The matter will depend on whether the property actually belonged to you or not, who is the actual owner of the property, what is your status? If the property is not yours, then how long have you been in possession of the property in question!
If the property has been sold by the actual owner to A, and B has sold it to B, then there is no illegality, even if he does'nt have the possession.
If he is not the actual owner, then it is a fraud. If you are an owner then you can challenge his sale deed with the actual papers and get a stay from the court on his actions.
If you are a tenant, then B has the right to get you evicted off the property through court's order. The fight is b/w the actual owner and B.
The information is very less and thus these ar the possibilities i could express. Please disclose complete information for more certain advice.