Sir

Show the document to a local prudent lawyer for better appreciation of facts and professional advise/ required proceeding.

That is just bogus, land neither can be sold nor transferred by way of such stale peice of paper. For sale of land you need to execute a sale deed. Just occupy your land and no one is going to interfare, if he tries to obstrcut you lodge an FIr and mention that he manuplated the document.

If you signed the paper and he filled thed etails in that about sale purchase, that may be treated as a consideration, which you can challenege always.

Just forget hin tell him to do what he can , 

It is your moral obligation and responding to a good gesture of a friend, in helping you while you are in distress and whether he has exploited you or not the issue in mutual obligations.  You can first morally repay the amount and then face/defend to protect your property.

For proper advice, we need to see the document signed by you. However, it may be stated that there cannot be the sale of immovable property by an affidavit. 

Yes, any meaningful suggestion requires the document be perused.

In response to your query, 

A sale cannot be executed without a sale deed and to acquire a sale deed it is mandatory that the owner had original documents of the ownership of the property. An affidavit cannot be considered as an original document of ownership. Therefore I believe that in your case no sale has taken place and no one can force you out of your property but just be careful I would suggest you to first return the money that you borrowed and then claim the ownership of the property so that the other person doesn't frame for anything like money fraud or anything else and then you can take a legal action against him if he tries to claim your property. 

Regards,

Aryan Raj 

has the paper been registered in Tehsil as sale deed.