testdb.php

<?php

class con
{
    public $con;
    public function __construct(){
        $con = mysqli_connect('localhost', 'root', '', 'whatsapp');

        if($con){echo 'Connection <br/>';}else{echo 'Problem Connection <br/>';}

        if (mysqli_connect_errno())
        {
        echo "Failed to connect to MySQL: " . mysqli_connect_error();
        }}
    public function conQuery($conQuery){
        return mysqli_query($this->con,$conQuery);
    }
}
    $c = new con();
    $r = "INSERT INTO `send`(`id`, `packets`, `phone`, `typ`, `send`, `dat`) VALUES (null,'111111111','22222222','text',0,'1/1/1')";
    $e = mysqli_query($c->con,$r);
    if ($e) {
        echo 'ok';
    } else {
        echo 'no';
    }

change the construct like this :

class con {

public function _construct() {
            $con = mysqli_connect('localhost', 'root', '', 'whatsapp');

        if($con){echo 'Connection <br/>';}else{echo 'Problem Connection <br/>';}

        if (mysqli_connect_errno())
        {
        echo "Failed to connect to MySQL: " . mysqli_connect_error();
        }
        $this->con = $con;
}
}

when use the class do:

$c = new con();
$q = "select * from test";
$e = $c->conQuery($q);
... # your other code here