stock payout after death of client

[merc70]

My mother died in 2000. I am the executor of here estate. After her death I was contacted by h&r block who stated my mother had stock in olde corporation which they purchased in the late 1990s. They wanted to close her account and pay me the funds that were in it which they did. eight months later they sued my mothers estate and myself stating they made a mistake and that it was not my mothers money. unfortunately a judge sided in their favor and a lean was placed on my home. I fired my attorney who handled the case for there was many red flags regarding h&r blocks claim and how my attorney responded. this occurred in 2003. this past summer i came across a document with an account number for olde corporation that was in my mothers name from 1998. it does not have a dollar amount on it but it proves my mother did have stock in olde corporation before h&r block bought the company. HOW CAN I RESEARCH THE COMPLETE HISTORY OF THE FORMER OLDE ACCOUNT??