Excel Spreadsheet Repair and Upgrade for M&A

I have a complex excel document that I created several years ago to help me calculate labor and non-labor synergies for companies that are purchased through M&A. The excel file has been modified so many times that many of the formulas are broken and it does not work like it used to. I'm looking for a contractor with excel expertise that is focused and has the capability to fix and fortify the spreadsheet so it can be used for acquisitions long into the future.

Key Issues:
- Broken formulas
- Functionality issues
- Incorrect formulas and references
- Unused functionality

The ideal freelancer for this project should have:
- Exceptional Excel skills
- Experience with M&A calculations
- Ability to enhance functionality
- Ability to suggest and implement new features
- Skill in identifying and removing unused features