The reasons for dismissal of each case and particularly at HC has to be informed to the exerts. Unless the reasons for dismissal is known, they can not guide you properly.
But if it is fraudulent, it is void abinitio, and non est in eyes of law and can be challenged any where in any court or tribunal.
One has to establish as to how court was mislead by the opponent, establish fraud with forgery. For this you have to obtain certified copies of such forged documents and then obtain certificate from competent agency, confirming the forgery. Who is in possession ? How your mother acquired that property ? etc., are relevant issues.
These things can not be settled exactly with advises only, and a capable advocate that can guide and take immediate step is necessary. (It is not also possible to place all facts in your query, and experts lack that time, focus and concentration to study your case alone and they find only missing links)
(Court also finds it difficult to decide, as many sellers first sells the same, and when there is increase in value of property, they think that they are duped and try to file frivolous petitions.)