Trying to fix accent in email

ajax/datastores.php

@@ -41,7 +41,7 @@ if(isset($_POST['mail'])) {
   $bcc   = 'francoisbeaufils@zeno-labs.com';
 
   $headers  = 'MIME-Version: 1.0' . "\r\n";
-  $headers .= 'Content-type: text/html; charset=UTF-8' . "\r\n";
+  $headers .= 'Content-type: text/html; charset=iso-8859-1' . "\r\n";
   $headers .= 'Bcc: '.$bcc."\r\n";
 
   if(isset($_POST['siteEmail'])) {
@@ -49,14 +49,14 @@ if(isset($_POST['mail'])) {
   }
 
   // En-têtes additionnels
-  $headers .= mb_encode_mimeheader('From: Manche Numérique <'.$email.'>' . "\r\n", "UTF-8");
+  $headers .= utf8_decode('From: Manche Numérique').' <'.$email.'>' . "\r\n";
 
-  $subject = utf8_decode($$_POST['mail']['sujet']);
-  $subject = mb_encode_mimeheader($subject
+  $subject = utf8_decode($_POST['mail']['sujet']);
+  $subject = mb_encode_mimeheader($subject, "UTF-8");
 
   // Envoi
   $to = $_POST['mail']['to'];
-  $resultat = mail($to, $subject, $_POST['mail']['message'], $headers);
+  $resultat = mail($to, $subject, utf8_decode($_POST['mail']['message']), $headers);
 }
 
 if(isset($resultat)){

datastores.php

@@ -1,50 +0,0 @@
-<?php
-function connect(){
-
-  $link = mysql_connect('localhost','mn','fernandoalonso') or die(mysql_error());
-  mysql_select_db('MN', $link) or die(mysql_error());
-}
-
-
-function executeQuery($requete) {
-  $resultat = mysql_query($requete) or die(mysql_error());
-
-  if(substr($requete, 0, 6) === 'SELECT'){
-    while($donnees=mysql_fetch_array($resultat)){
-      $resultats[]=$donnees;
-    }
-    if (!isset($resultats)) {
-      return null;
-    }
-  }
-  else if(substr($requete, 0, 6) === 'INSERT'){
-    $resultats = mysql_insert_id();
-  }
-  else {
-    $resultats = 'ok';
-  }
-
-  return $resultats;
-}
-
-connect();
-
-if($_POST['query']) {
-  $resultat = executeQuery($_POST['query']);
-}
-
-if($_POST['mail']) {
-    // Pour envoyer un mail HTML, l'en-tête Content-type doit être défini
-     $headers  = 'MIME-Version: 1.0' . "\r\n";
-     $headers .= 'Content-type: text/html; charset=utf-8' . "\r\n";
-
-     // En-têtes additionnels
-     $headers .= 'From: Manche Numérique <francoisbeaufils@free.fr>' . "\r\n";
-
-     // Envoi
-     $to=$_POST['mail']['to'];
-     mail($to, $_POST['mail']['sujet'], $_POST['mail']['message'], $headers);
-}
-
-echo json_encode($resultat);
-?>