My mother gained access to MY life insurance policy, managed to cash it out and announced she is splitting it amongst my siblings. What grounds do I have?

I want to start by saying this is real, not rage bait. When I was a baby, my grandmother took out a Prudential life insurance policy on me. There was never full clarity communicated to me of the policy number, or the amount it contained, but she would communicate to me fairly frequently that this policy existed, just never how to access it, even going so far as to tell me in my mid 20s "if you ever needed money for grad school, you could borrow against it" and "if you ever got sick, you could borrow against it". My mom (her daughter) was also listed on the policy, in case I died as a child or minor. My grandmother died recently, in her 90s. Despite having interacted with my mom many times since then, even a few weeks ago, I have not heard anything about the life insurance policy, as the estate has settled out...Until last night. I'm in my hometown visiting my parents for the holiday. My mom glibly announced last night that she, with the help of a distant family member who has a finance background and is the executor of the estate, managed to make it through the Prudential phone tree, and cashed out my life insurance policy. I was stunned. She then commented, "the market is down, so if they'd let me talk to someone who spoke english and I'd managed to do this two weeks ago, it would have been worth 3k more." I was livid--my understanding is that could have likely been rolled into something else, and worth more, and also, taking something out when the market is down is not the move. She then continued, "Your grandma always felt bad she didn't take a life insurance policy for your younger sisters (My brother and I were born in the early 90s, my sisters were "surprise babies" my mom had in the early 2000s,), so she wanted the policy to be split between you and your sisters. So that's what I'm doing when the check arrives." Just like telling me, not asking. I was also shocked bc She has not mentioned any of this, if it was truly grandma's will, and i literally just