diff --git a/backend/app/Controllers/WhatsAppController.php b/backend/app/Controllers/WhatsAppController.php
index c10b48b..4046a77 100644
--- a/backend/app/Controllers/WhatsAppController.php
+++ b/backend/app/Controllers/WhatsAppController.php
@@ -17,8 +17,7 @@ class WhatsAppController extends BaseController
     public function status(Request $request, Response $response)
     {
         $companyId = $request->company_id; // Added by AuthMiddleware
-        $sessionModel = new WhatsAppSession();
-        $session = $sessionModel->findOrCreate($companyId);
+        $session = WhatsAppSession::findOrCreate($companyId);
         
         // Strip sensitive/internal data before sending to frontend
         unset($session['phone_hash']);
@@ -35,11 +34,10 @@ class WhatsAppController extends BaseController
     public function requestQr(Request $request, Response $response)
     {
         $companyId = $request->company_id;
-        $sessionModel = new WhatsAppSession();
-        $session = $sessionModel->findOrCreate($companyId);
+        $session = WhatsAppSession::findOrCreate($companyId);
         
         // Temporarily set to connecting
-        $sessionModel->updateState($session['id'], ['status' => 'connecting']);
+        WhatsAppSession::updateState($session['id'], ['status' => 'connecting']);
         
         // Call Baileys Node.js Service on port 3722
         $nodeUrl = 'http://127.0.0.1:3722/api/sessions/start';
@@ -69,7 +67,7 @@ class WhatsAppController extends BaseController
             ]);
         } else {
             // Revert state on failure
-            $sessionModel->updateState($session['id'], ['status' => 'disconnected']);
+            WhatsAppSession::updateState($session['id'], ['status' => 'disconnected']);
             $response->status(500)->json([
                 'status' => 'error',
                 'message' => 'Failed to reach WhatsApp Gateway.'
@@ -83,8 +81,7 @@ class WhatsAppController extends BaseController
     public function disconnect(Request $request, Response $response)
     {
         $companyId = $request->company_id;
-        $sessionModel = new WhatsAppSession();
-        $session = $sessionModel->findByCompany($companyId);
+        $session = WhatsAppSession::findByCompany($companyId);
         
         if ($session && $session['status'] !== 'disconnected') {
             // Call Baileys Node.js Service to disconnect
@@ -103,7 +100,7 @@ class WhatsAppController extends BaseController
             curl_exec($ch);
             curl_close($ch);
             
-            $sessionModel->updateState($session['id'], [
+            WhatsAppSession::updateState($session['id'], [
                 'status' => 'disconnected',
                 'qr_code' => null,
                 'phone' => null,
@@ -132,8 +129,7 @@ class WhatsAppController extends BaseController
             return;
         }
 
-        $sessionModel = new WhatsAppSession();
-        $session = $sessionModel->findBySessionKey($body['session_key']);
+        $session = WhatsAppSession::findBySessionKey($body['session_key']);
         
         if (!$session) {
             $response->status(404)->json(['error' => 'Session not found']);
@@ -155,7 +151,7 @@ class WhatsAppController extends BaseController
             $updateData['qr_code'] = null;
         }
 
-        $sessionModel->updateState($session['id'], $updateData);
+        WhatsAppSession::updateState($session['id'], $updateData);
 
         $response->json(['status' => 'success']);
     }
diff --git a/backend/app/Models/Contact.php b/backend/app/Models/Contact.php
index f52e419..1049e54 100644
--- a/backend/app/Models/Contact.php
+++ b/backend/app/Models/Contact.php
@@ -10,7 +10,7 @@ use App\Core\Security;
  */
 class Contact extends BaseModel
 {
-    protected string $table = 'contacts';
+    protected static string $table = 'contacts';
 
     /**
      * Create a new contact with encryption
diff --git a/backend/app/Models/WhatsAppSession.php b/backend/app/Models/WhatsAppSession.php
index e5639d7..289a0d6 100644
--- a/backend/app/Models/WhatsAppSession.php
+++ b/backend/app/Models/WhatsAppSession.php
@@ -4,23 +4,25 @@ namespace App\Models;
 
 use App\Core\Security;
 
+use App\Core\Database;
+
 /**
  * WhatsAppSession Model
  * Handles the whatsapp_sessions table with encryption for phone and QR code.
  */
 class WhatsAppSession extends BaseModel
 {
-    protected string $table = 'whatsapp_sessions';
+    protected static string $table = 'whatsapp_sessions';
 
     /**
      * Get the session for a specific company
      */
-    public function findByCompany(int $companyId)
+    public static function findByCompany(int $companyId)
     {
-        $session = $this->db->query(
-            "SELECT * FROM {$this->table} WHERE company_id = ? LIMIT 1",
+        $session = Database::selectOne(
+            "SELECT * FROM " . static::$table . " WHERE company_id = ? LIMIT 1",
             [$companyId]
-        )->fetch();
+        );
 
         if ($session) {
             $session['phone'] = $session['phone'] ? Security::decrypt($session['phone']) : null;
@@ -33,12 +35,12 @@ class WhatsAppSession extends BaseModel
     /**
      * Get a session by session_key (used by webhooks)
      */
-    public function findBySessionKey(string $sessionKey)
+    public static function findBySessionKey(string $sessionKey)
     {
-        $session = $this->db->query(
-            "SELECT * FROM {$this->table} WHERE session_key = ? LIMIT 1",
+        $session = Database::selectOne(
+            "SELECT * FROM " . static::$table . " WHERE session_key = ? LIMIT 1",
             [$sessionKey]
-        )->fetch();
+        );
 
         if ($session) {
             $session['phone'] = $session['phone'] ? Security::decrypt($session['phone']) : null;
@@ -51,29 +53,29 @@ class WhatsAppSession extends BaseModel
     /**
      * Create or retrieve a new session for a company
      */
-    public function findOrCreate(int $companyId, string $name = 'Main WhatsApp')
+    public static function findOrCreate(int $companyId, string $name = 'Main WhatsApp')
     {
-        $session = $this->findByCompany($companyId);
+        $session = static::findByCompany($companyId);
         if ($session) {
             return $session;
         }
 
         $sessionKey = 'cmp_' . $companyId . '_' . bin2hex(random_bytes(4));
 
-        $id = $this->create([
+        $id = static::create([
             'company_id' => $companyId,
             'name' => $name,
             'session_key' => $sessionKey,
             'status' => 'disconnected'
         ]);
 
-        return $this->findByCompany($companyId);
+        return static::findByCompany($companyId);
     }
 
     /**
      * Update session state securely
      */
-    public function updateState(int $id, array $data)
+    public static function updateState(int $id, array $data)
     {
         if (isset($data['phone'])) {
             $data['phone_hash'] = Security::blindIndex($data['phone']);
@@ -84,6 +86,6 @@ class WhatsAppSession extends BaseModel
             $data['qr_code'] = Security::encrypt($data['qr_code']);
         }
 
-        return $this->update($id, $data);
+        return static::update($id, $data);
     }
 }