How can I find out if a family member left me money that was stolen by my aunt?

In 2009, my male cousin slipped up and mentioned money that he received from a deceased family member, but when I tried pruning him for more details, to check on money's due my brother and I, he quickly changed the subject, and all of a sudden had a quick errand to run. In 2010 my female cousin acted as though she was being family oriented, by first asking all the "long time no hear from" questions, then eventually asked for my birthday, right after I typed it in, she deleted our Facebook conversation and stopped chatting with me. Although weird, I didn't think nothing more about it, and moved on. August 18, 2018 my aunt mails me a probate waiver form, this time, my antennas rightfully went up, and I refused to sign it, not understanding with the other 2 incidents. Come to find out, or great uncle had passed and we inherited money, which I believe she was tricking me about once again. What can I do?