Hi Arwen,
Sorry to hear that. While OneDrive does have a Recycle Bin where deleted files are stored temporarily (usually for 30 days), if the files were permanently deleted and that time has passed, recovery becomes very difficult. Microsoft typically does not retain backups of permanently deleted files beyond that window.
Go to onedrive.live.com and check your recycle bin and 2nd stage recycle bin (only for work/school accounts) if you were able to find some files/photos there.
However, since this was a case of fraud, I strongly recommend contacting Microsoft Support directly. They may be able to investigate and assist further, especially if the deletion was recent or if you had a Microsoft 365 subscription. You can reach them here: https://support.microsoft.com/contactus