Hebrew email from Mac to Windows

I communicate with a Mac user. I use Windows. Each of us can write
emails in Hebrew, but we cannot decode each others Hebrew messages.

My email software is Mozilla Thunderbird. I have the following
Hebrew encoders listed, but none of them work on Mac messages.

ISO 8859-8
ISO 8859-8-1
MacHebrew
IBM 862

Can anyone help ? I could forward an example of an email I have
received.