That's weird.
First thing to do is change your passwords. Make sure the new passwords are strong.
Don't store the passwords on your PC. Write them down
Have you discussed recovering your data with QB support?
It is probably not worth doing however, as with that low volume of missing transactions could be re-entered more quickly than performing a restore.
Data restores on accounting systems can get messy if you have entered transactions after the backup date.
The thing you might have to be concerned about is a keylogger program (or device) installed on one of your PC's that you use to access QB Online. If the password keystrokes are sent to a bad actor, they would continue to be able to log into your Quickbooks even after you change your passwords. (Are you paranoid yet?)
First thing to do is change your passwords. Make sure the new passwords are strong.
Don't store the passwords on your PC. Write them down
Have you discussed recovering your data with QB support?
It is probably not worth doing however, as with that low volume of missing transactions could be re-entered more quickly than performing a restore.
Data restores on accounting systems can get messy if you have entered transactions after the backup date.
The thing you might have to be concerned about is a keylogger program (or device) installed on one of your PC's that you use to access QB Online. If the password keystrokes are sent to a bad actor, they would continue to be able to log into your Quickbooks even after you change your passwords. (Are you paranoid yet?)