File suit to set aside sale deed executed by second wife and her children 

2) you have one seventh share in property 

3) also apply to authorities for setting aside legal heir certificate issued as your name is not reflected as legal heir 

Yes,  First take the injunction from court on sale deed of property and stop the sell transaction informing to SRO.

You are eligible to get 50% share of you father's property as per the Indian Succession Act, Class I heirs list.

1. Since the property inherited by your husband was ancestral and he died intestate you have equal rights with your step mother and step siblings. 

2. Now if any property is still left or all are sold then without delay file a suit for partition and injunction and for setting aside of the sale deed. 

3. Legal heir certificate does not have much significance and you can also get similar certificate by making fresh declaration. 

Yes u can get by showing family chart... Because u can also claim your right

Please file Succession certificate making all if them a necessary party to your step mother and all her children for division of property as Hindu Succession Act 1956.

You are entitled to the share of ancestral property. 

Regards 

G.Rajaganapathy 

High Court of Madras 

Which year property sold ? 

You have equal share in the property I.e 1/7share each. You should have filed suit for cancellation of sale deed.

Legal heir certificate is forged and invalid without you mention as legal heir.

You should submit your objection to LHc issuing authority and request them to file FIR agaisnt wife for submitting false and incomplete information to obtain favorable LHC.

Dear Sir/Madam,

It is suggested that you file the suit of declaration against the step mother and the said buyer of the property and ask for the share in that property.  

First, please make a written request to the Tahsildar who had issued the legal heirs certificate asking for inclusion of your name. If refused, complain to his higher authorities such as the DRO and the District Collector. If still there is no remedy, you may approach the High Court under its Writ jurisdiction for suitable directions to the authorities concerned.

Firstly the sale of property that your father left behind without giving a share in the sale consideration amount is illegal and invalid.

You do not have to cancel the legal heirship certificate.

You can file a partition suit seeking partition of entire property and to allot one such equal share in the property with good and bad soil and separate possession.

File a partition suit. You will get your share.

seek court order for declaring the legal heir certificate as null and void. 

You need to file partition suit against your step mother and siblings to claim your share from properties of your father. 

It can only be cancelled if obtained by fraud, misrepresentation and giving incomplete knowledge to court

A suit for cancellation of sale deed must be filed immediately making them parties.

A criminal complaint against them must also be filed for fraud and forgery and cheating.

No it's not possible.