Looking for Transfer Agent Assistance

Please forgive if this isn’t allowed. Pointing me in the right direction would be appreciated. I found an old stock certificate in a drawer of my late mother’s desk. I contacted the Transfer Agent on the certificate, and completed the documentation to transfer the stock to me. I have no idea if the certificate still has value. In any event, the certificate was returned by the Transfer Agent listed on the certificate with a note directing me to a different Transfer Agent. That entity has no record of the certificate number or an account in the name on the certificate, although they do currently handle transactions for the company on the certificate. They had no advice or suggestions, and could not tell me if the certificate has any value. No idea what to do next. TYIA.