if evidence of fraud and self dealing are found after successor trustee closes the trust, how can i request a full detailed accounting of the trust

My mom owned 3 homes, two in US a and one vacation home In mexico worth $500,000.00. There was ongoing argument between my mother The trustor and my brother successor trustee. My mom wanted to sell all three and us three adult kids split the money. My brother did not Want mexico. Home sold, my mom was going to sell it. When she died the home was listed for sale. She died before it sold. My brother Canceled the sale and decided not to sell it. It was nowhere on the asset and property acct and it wasn't included in the estate value And it left us out of a big part of our inheritance. After trust closed he sent me a bogies Mexican will lowering my share from 33.3% Owner to 20% and he raised his and my sisters to 40%since only I opposed keeping it and says I no longer have any say in how They decide to proceed. He won't respond to anything regarding the property or anything else. 80% of all my moms assets were Unaccounted for. What do I do?