Really surprising. In fact, before purchasing the property, the intending purchaser should execute an agreement to sale and get the title clearance certificate in relation to the property sought to be purchased. If you do not undertake such basic steps, such things are bound to happen. Now that amicably settle all issues with the intending seller and gather the information as to how much dues are outstanding. He is required to get all clearance. Did you ever execute an agreement to sale? Have you got the receipt for payment of consideration in exchange of property? Now that you will have to undertake all exercise. If the intending seller has a high moral, there will be no difficulty, otherwise, you may have to resove the issue through litigation. (This is the contigency that I have expressed)