Recover Admin Access to Management Solutions

I know that several crucial spreadsheets carrying *special* administrative command instructions are out there, still shared with others, yet I no longer hold sole edit rights. It exists on management solutions and information systems ERP systems online... (Budget: $30 - $250 NZD, Jobs: Cloud Computing, Data Management, Data Recovery, ERP, Excel, Human Resources, Management, Microsoft 365, Microsoft Access, Sharepoint)