@minusten, your script is rather cumbersome. You are concatenating variables, dispite them already being in double quotes (to interpolate them). You also could use the predefined constant PHP_EOL, so that there will be a carriage return regardless of what architecture you are working on.
Here is a script that is a lot more optimised:
What you will notice in my script above is that I do not bother concatenating or interpolating variables. This means there is no resource overhang for php when try to parse the variable $body.
$body = 'Client Name: ',$Fname,' ',$Lname,PHP_EOL,