Family member may have stole my inheritance and idk how to get justice. What do i do?

[idekwut2put_atx]

Ok is a long story but basically me and my sis were supposed to get everyone my dad had after he died but we were 13 yrs old at the time. And he designates his brother, my uncle, to be the executor(person in charge of making sure that happens) of his estate. So time goes on and about 17yrs later my grandma finds and gives to us each a contract to pay out when we turn 18 for about $35,000.00. And we never got anything close to that amount of money ever. So we called them and they say it had been paid out when we turn 18. So we say send the paperwork you have on this. Turns out they sent checks to an address they thought was our address to california po box. And the checks were cashed in Texas where we live, into our grandpas bank account. The reason they thought it was our address was because my grandpa filled out the claim for the money and put our info and signed our names, at least that's what it looks like. (even though we were supposed to do it out but we hadn't known about it). and then also signed it as the witness. But he put the po box as our addresses . (Sidenote: he got most of the other info wrong about me including my bday, ssn, date of death, etc. ) my reasoning for saying my uncle the executor had a part is bc he had access and he is the only one who has ever lived in California in out family. So it's probably his po box.
So to Summarize just from what it looks like from my point of view, my grandpa does it the claim form for my insurance payout when i turned 18 and was eligible to recieve it, or my address as my uncle's, he recieved my mail and opened it and sent the checks to Texas across state lines and somehow cashed ut and deposited itinto my grandpas bank account. And after that we don't know what happened to it but i never got it. Since then my grandpa has died but my uncle is alive still

[nobarakugisaki]

How about consulting a lawyer