Is it advisable to lodge FIR

My maternal grandmother used to live with her son. From 2015 she went missing. Police did not take complaint from my mother at that point of time since she(my maternal grandmother)didn't live with my mother. So my maternal uncle with whom she used to live became the obvious choice for missing complaint. After some days he(my maternal uncle) started to claim that he lodged a complaint but refused to provide a copy of that to my mother. After repeated failure, we, being frustrated, filed a RTI PETETION to the police. They stated no such missing diary was lodged at that point of time. A followed up petetion in police station revealed that a complaint was lodged in 2011 and I have obtained a photocopy of M form of missing record in 2024. But in 2011 my maternal grandmother was perfectly fine and present in her house. We frequently conversed with her in person till June,2015. Now my question is whether it comes under the category of a cognizable offence and we can file FIR or it falls under the category of non cognizable type .