Firstly take out the documents which she has filed along with her appeal. She must had filed some proofs along with her application before the District Court try to get that said documents and than file a review petition in the High Court.

If she has taken the said succession certificate by playing fraud upon the court you move for cancellation of the same on ground of fraud

Birth certificate ,school leaving certificate ,Aadhar card would reflect name of the biological parents 

you have to make application to court to set aside succession certificate issued to her 

Unless and until you disprove the marriage , you claim to the assets of your uncle and aunt will not stand.

So gather information as regards the basis of claim of this person. If you find the proof she gave in court was false you can file a suit to declare it null and void. 

You may first collect all the documents she filed before court by engaging an advocate with a third party affidavit and vakalatnama given to the advocate.

Scrutinize the details and on the basis of the discriminatory information you may file a petition before the same court to set aside the orders for the fraud played by her on the court.

Besides, just merely being a Nominee you cannot claim their assets, you may have to obtain a succession certificate in your name through court if you stake a claim to the assets of the deceased.

1. Before grant of succession certificate, Court directs the petitioner to issue a public notice in local newspapers for objections from interested parties to grant of succession certificate
2. Check the record of Court to ascertain if any such public notice is issued, you can claim that you don’t subscribe the  newspaper in which such notice was issued.
3. She is required to file documentary proof of her relationship with aunt or uncle through, birth certificate, aadhar card, education certificates, ration card etc. She is also required the establish relation of husband and wife  of previous marriage through documents like PAN card, aadhar of aunt or uncle. Check on what basis the  Court was granted succession Certificate.
4. File a suit for cancellation of succession certificate in the  Court that granted her succession certificate challenging all documents filed by her.
5. In the suit you are required to add bank as second defendant, the  first being the person  who obtained such certificate.
6. You can also seek matching of your DNA sample with her, as nephew you DNA should match with her since she is claiming to be daughter your uncle/aunt.
7. From your question it is not clear whether she is claiming daughter of uncle or aunt.

Being nominee you can only receive the money but is legally bound to handover and distribute the same among class-1 legal heir of deceased. You can challenge the succession certificate granted to girl by filing appeal etc.

Steps to Challenge the Fraudulent Succession Certificate:

1. 
   File for Cancellation – Petition the High Court under Section 383 of the Indian Succession Act citing fraud and misrepresentation.
2. 
   Prove No First Marriage/Daughter – Collect:

   • Marriage records, legal IDs, and family affidavits.
   • Claimant’s birth certificate to verify parentage.

3. 
   Police Complaint (If Fraud Suspected) – File under IPC Sections 420 & 468 for cheating and forgery.
4. 
   Recover Assets – File a civil suit to reclaim money and gold.
5. 
   Appeal if Needed – Challenge in a higher court if rejected.

Act quickly and consult a civil litigation lawyer in Bangalore.

For detailed, personalized advice, consider a phone consultancy. Hope you find the information helpful. You are free to contact me for further discussion. If you could spare two minutes of your time to write a review, it would be greatly appreciated and bring immense happiness to read it. Thank you. Shubham Goyal.

- You should try to get the copies of the documents submitted by her before the Court for obtaining Sucessession certificate.

- If those documents are not genuine then file a complaint before the Police 

- Further, you can move an application after submitting the said copy of the complaint before the same Court to cancel the said certificate. 

1. Before grant of Succession Certificate the court of District Judge where the petition was filed must have ordered the publication of summons of the case in a national and regional newspaper as the petition must have been filed against general public. The court issues a notice, which is to be published in a news paper, to the effect that the specified period of rising an objection is 45-days. In the absence of objections from the heirs served with the notice, the petition shall be upheld and a Succession Certificate shall be issued on the heir-applicant. If there are any objections raised, the Court would hear them and decided on the same. 

2. Notice to general public through publication in newspaper is considered sufficient notice.

3. The Succession Certificate once issued cannot be contested again or revoked. But if the issuance is made in the absence of jurisdiction or by fraud it can be set aside at the instance of the aggrieved party by making a proper application to the Court to set the same aside.