Questions of evidence. Evidence of other wrong doings is generally inadmissible in Court (although in a small claims setting, the rules of evidence don't really apply)
Receipts are not necessary, although they do make your burden of proof lighter. Also remember, its the value of the property AT THE TIME OF CONVERSION, not what it cost you to purchase it.
A proper response would require a much more thorough and complete investigation into the history and facts set forth in your question. Any statements provided by me regarding your inquiry is nothing more than an opinion, and does not represent legal advice or create a client relationship.