Missing statements and information

My grandfather left everything to his second wife, when she died 10yrs later she left 1/2 to her son and 1/2 to my grandfathers 3 children. All have deceased. I found there was royalties waiting to be distributed under my grandfathers name. I obtained all legal documents and filed in behalf of my cousins. I found there were years of royalties that are unaccounted for. The wife’s did not probate his mothers will and it is believed he received the royalties until his death. I can not trace this money back. I do not know whom to contact. Oleze of Illinois is the producer I believe and no one in the company will call me back. Where can I find this information. Also, I understand 1 well is dry. I would like to find out if anything has been done to revive it. Can anyone help