Real Estate / Polish law on inheritance and real estate [42]

Hi,
i was wondering if someone could help us please. my mother is polish and was adopted by my polish grandparents. they moved to england in the sixties and my grandparents went back to poland in the nineties. My grandad died seven years ago and my grandmother past away five weeks ago. My mother and sister went over for the funeral and were greeted by my grandmothers lawyer. my grandmother had already mentioned to my mum that she was going to leave quite alot to the church when she passed including maybe the house. On the day of the funeral the lawyer and a priest or someone to do with radio maria came to pick them up and take them to the town where she was getting buried. Obviously my mum was very upset that day, and on the way to the funeral the priest showed my mum a envelope with my grandmothers will in it already opened. It was in her handwriting and it said the house was getting left to radio maria and all the belongings were getting left to her cousins and their family's. They asked my mum to sign something, she cant remember what it was, but because her head was all over the place with it being the day of the funeral, she just signed it. Now i dont know the law of whether the will has to be read out in front of everyone who was on it, or it has to be in a office. I also want to know why the priest had it and it had already been opened. My mother didn't get mentioned in the will or neither did myself, sister or our children. When my mother mentioned this to my grandmothers neighbours and friends, they were quite shocked as all my grandmother ever talked about where her daughter, grandkids and great grandkids. The lawyer also wanted my mother to take all her adoption certificates over and he took them off her and gave them back before she headed back home. He said he would send everything over to her in the next week, i.e death certificate, copy of will etc, but after five weeks and several e-mails he hasn't sent anything over. We just found out yesterday that he picked the keys up of the neighbour and was going around with a estate agent measuring and taking pictures of the house ready to put on the market. We was wondering if there was anything we could do to detest this until we had all the proper paperwork ourself and to see if there was anything due for my mother. The neighbour told us of a law 'zachowek'. my mother also brought home loads of pictures and paperwork in which she found a will from early 1990's leaving the estate to her and kids. she cant remember what date was on the will the priest showed her a couple of weeks ago. if anyone could help us that with wha legal rights she's got that would be great. thanks