retrieve that file

i created a function to send that file to some other server thru API call, so i just want to retrieve that file and send it to that server. i used this code

if ($contact_form->id() === $form_id) {
$submission = WPCF7_Submission::get_instance();
if ($submission) {
$posted_data = $submission->get_posted_data();
$files = $submission->uploaded_files();