Resolved Question: I think my Mom is hiding money left to me by my deceased Grandmother!?

My Grandmother passed away almost 5 years ago. We were very close. She basically raised my sister and I. I had a baby at 17 and she was there every step of the way to help me. She was crazy about my boy and spoilled him rotten. We would spend 5 out of 7 days a week together. I was always there for her and she was always there for me.
When my Grandma got sick(cancer) I was there for her running back and forth to the hospital and school making sure she had everything. My mother nor anyone else was there for her in the beginning. I was devastated when we lost her. She was a very important part of my life. I miss her very much.
When she passed she had a will. It was very simple. She stated that everything be split 50/50 between my mom and my aunt. That’s it. Very simple.
My mother is a very greedy woman. She hasn’t worked in years. She is an alcoholic. I have not spoken to her in almost 2 yrs. She has never liked my boyfriend and at one point told me that if I were to stay with him she would cut me out of her own will.
What I don’t understand is that my sister was left money. My Grandma worked for the Gov. for years and was laid off so she received a nice payout deposited into her account monthly until 2012. Im not to sure how it worked, my sister said someone phoned her and said the money was left to her. She then went down and had it transferd into her name/account. She said it was being paid monthly 4 yrs ago and recently told me that she took the pay out. I feel like im being lied to. My mom kept telling me don’t worry Im sure Grandma left something for you we will find it.
My aunt and Mom HATE each Other. There is no communication between either of them. I asked my aunt about the money left to my sister and she said it was weird. Then she said that she saw the forms and they did have my sisters name on them but had a post it stuck on it with my name on it as well but it was void because it was on the post it. Everything seems fishy.
My mother had garbage bags full of Grandmas papers she was shredding. Grandma was ahoarderr and kept all her important papers in her house. My mom wanted all she could get and felt my aunt wasn’t deserving of any of it. Moms still staying in Grandmas house with my sister and my sisters boyfriend. She feels she has the right to it all and when I was still talking to her all she wanted to do is find ways to screw my aunt out of money. So whywouldn’tt she screw me over. I was sooo close to Grandma, the first born grand child. Why would she leave money to my little sister and not me as well. I feel like the black sheep.
My mom had found ALOT of old coins in the attic and told me she wanted to sell them and split the money with me anddidn’tt want me to tell my sister. I said that itwasn’tt fair and told my sister anyway. I saw nothing of course. She wanted to hide things from her whywouldn’tt she do the same to me?? There was $1600 in cash that was in the house with my sons name on it.It was in 5 dollar bills and old 2 dollar bills. She said she would take it to a friend to sell it for a bit more because it was in sequence. I trusted her and to this day almost 5 years later did notreceivee his money.
Im wondering if maybe there is something there. Maybe an RRSP (she has many and they keep maturing.There was always mail going to the house saying how much they were maturing) How would I find out? My mom would never tell me. My aunt says she knows nothing. My sister acts clueless. The bankfrozee everything years ago because my mom was spending money out of the account. Would the bank know? Would they have called me already even if everything was on hold? It also took forever for them to get the probate done. Im not to sure how all of this works. I just feel like somethingisn’tt right! What can I do?