Can a registered Will be challenged by 2 brothers

We are total of 3 brothers and 3 sisters. My mother passed away 2 years back. She did a vasiyat in only my name in 2012-13, because the shares were already given to my 2 brothers. But after she passed away, my brothers refused to sign and agree to get it transferred to me. So, I did a case in Tehsil court. In around 6 months Tehsildar gave decision without hearing any gawahis, that it should be divided into all 6 brothers and sisters. I am sure that my brother gave bribe to the Tehsildar, and within 2 days all their names were listed in Khasra. Now, I did case in Nyayalaya(Hoping of no bribe here). Now the issue is with the court. My brothers claimed that my mother was not well and I forced her to sign the will. But that's not the case. Since she already divided and shared her property to all 3 of us. They have transferred it in their names but left over property given to me was in my mother's name, I only took care of her. To get the justice, what should be my next step?