Hi Stacy, I can imagine how stressful and overwhelming this must feel you’ve built your business around those files and now they’re locked away in an account you can’t access.
To get your old Microsoft account and OneDrive files back, first check if the account still exists using the password reset page. If it does, fill out the Account Recovery Form with as much detail as possible from a trusted device. If that fails, contact Microsoft Support with proof like payment receipts. If the account was deleted within 30 days, restore OneDrive through the Microsoft 365 Admin Center or PowerShell; beyond that, use Files Restore or a backup service. As a last resort, legal action may be required.
Can you confirm if twostep verification was enabled on your old Microsoft account and whether you still have access to any recovery method like a phone number backup email or Authenticator app?
Best regards
Lucky Charm