can't open the illustration. Could not complete the request

[#1]

I've been working on an Illustrator file 4 days ago for work. I opened it today and the message "can't open the illustration. Could not complete the request" when i click "only a white artboard appears. I really need this file. Please how can it be fixed or recovered?

[#2]

I've been working on an Illustrator file 4 days ago for work. I opened it today and the message "can't open the illustration. Could not complete the request" when i click "only a white artboard appears. I really need this file. Please how can it be fixed or recovered?

[#3]

What is your operating system?

If you're on Windows you can use the Restore Previous Version 
https://support.microsoft.com/en-ie/help/17119/windows-7-recover-lost-deleted-files

Or if on the Mac you might have Time Machine running - 

https://www.macworld.co.uk/how-to/mac-software/time-machine-restore-3449071/

Did you not have any backups/previous versions of the files at all? Typically, I save files every hour or so under different version numbers.