Ok, so you will just need to add these two lines of code under line 19 of your page:
$WAFV_Errors .= WAValidateRQ(((isset($_POST["apellido"]))?$_POST["apellido"]:"") . "",true,8);
$WAFV_Errors .= WAValidateRQ(((isset($_POST["telefono"]))?$_POST["telefono"]:"") . "",true,9);
And then on line 87 change the "1" to an "8" and on line 103 change the "1" to a "9".
this will give you fields server side validation, you will just need to update the text that is shown for the validation.