in reply to MIME lite

Well, there are two obvious problems with what you have there.

The first is that the form action isn't going to mean anything as a relative URL in an email. You'll have to have a full URL there for it to have a chance of getting to your site (how can it know where your site is?)

The second is that you're passing the email body as a single-quoted string, so none of those variables are going to be interpolated. Maybe you should use a heredoc instead.

There are other weirdnesses (like what is that javascript 'back' function supposed to do in a mail client?), but those two are the obvious "this can't work" bits.