Required Legal Heir Certificate from Councilor of the local ward

That me and my father have a property at Gangajuara, Mouza - Tihuria, P.S. & P.O. - Sonarpur, South 24 Parganas, West Bengal. The particular land was mutated under our name in the ratio of 50:50 with two khatian nos. My father since deceased on 6th September, 2023 & I've already sold some parts of the land pertaining to my khatian No. and the same was mutated by the purchaser from Sonarpur BLRO. But when I sold a part of land from my father's portion of the said land their mutation was rejected due to absence of legal heir certificate from the local councilor. Though I have done a legal heir certificate from the District Magistrate regarding to this particular plot of land which belongs to my deceased father. I'm a single child and the only legal heir to my parent's property as my mother is also deceased since 28th April, 2002. Now the BLRO Officers is not acknowledging the Legal Heir Certificate made by the Ld.1st Class Magistrate. Now I went to the ward office so that the councilor would authorize me as the legal heir. But some of the members said that the local councilor do not have the authority any more to give the certificate. Kindly suggest how to sell the rest of the property of land.