Forgot PDF Password to Open

As the title states, I don't have the PDF password to open the PDF. The user left the company and didn't leave the password to the PDF that's full of important information. Any suggestions on something free that actually works? I've used several free programs that I googled with every one of them not working.

The PDF cannot be opened because of a password.

Have you tried stuff like this? http://www.pdfunlock.com/

smallpdf[dot]com can help you getting your file unlock.