$servername = "localhost";
$username = "root";
$password = "";
$dbname = "banco";

# cria conexão
$link = new mysqli($servername, $username, $password, $dbname);

# verifica conexão
if ($link->connect_error) {
    die("Connection failed: " . $link->connect_error);
}

# configura utf8 para caracteres especiais
mysqli_set_charset( $conn, 'utf8');

$contrato = '';
$nome = '';
$tel = '';

$sql_select = "SELECT contrato, nome, tel FROM teste WHERE contrato LIKE '%$contrato%' AND nome LIKE '%$nome%' AND tel LIKE '%$tel%' ORDER BY contrato;";

$r = $link->query($sql_select);

# Primeiro var_dump
# var_dump($r);
# exit();

if(isset($_POST["inserir"])){

    $sql_insert = "INSERT INTO teste (contrato, nome, tel) VALUES ("1000","João","DDD+número"); ";

    $sql_insert .= "INSERT INTO teste (contrato, nome, tel) VALUES ("1001","Maria","DDD+número"); ";

    $sql_insert .= "INSERT INTO teste (contrato, nome, tel) VALUES ("1002","José","DDD+número"); ";

    $link->multi_query($sql_insert);
    # header("location: .");
    $r = $link->query($sql_select);

    # Segundo var_dump
    # var_dump($r);
    # exit();
}
$link->close();

<form action="" method="post">
    <button type="submit" name="inserir" value="inserir">Inserir</button>
</form>

object(mysqli_result)#2 (5) { ["current_field"]=> int(0) ["field_count"]=> int(3) ["lengths"]=> NULL ["num_rows"]=> int(0) ["type"]=> int(0) }

bool(false)

object(mysqli_result)#2 (5) { ["current_field"]=> int(0) ["field_count"]=> int(3) ["lengths"]=> NULL ["num_rows"]=> int(3) ["type"]=> int(0) }