nasaan ba iyong original copy ng contract to sell and deed of sale? very risky ang may CAR na galing sa BIR at bakit mo babayaran ang capital gains tax at documentary stamp tax na hindi pa fully paid. I think once the certification authorizing registration (CAR) of the property is issued by BIR, the buyer can use that to transfer the property to his/her name. Wala ka ng habol sa full payment mo. Besides, BIR requires a receipt of payment on the sale which is from you and you haven't receive the full payment yet. May agreement ba kayo duon sa earnest money with terms and conditions as to execution of the deed of sale upon full payment and surrendering the owner's duplicate copy of the title? Kung meron, hindi dapat nagawa at napirmahan ung deed of sale. The earnest money is an agreement on the sale and is forfeited by the seller should the buyer cancel the sale agreement at no fault of the seller.
Note: I am not a lawyer, but just an ordinary person trying to share my opinion and experience that might be of help to you.