How to get value from form when using quickcheckout?

Question

opencart

Good afternoon, I ran into such a question ... how to add custom fields to a quick form)) And it seems like I added ... and the values ​​\u200b\u200bare taken ... but each time from the session. Those. the current value is equal to the previous order... and whatever one may say, I can't get it to reset these values. Maybe someone was tinkering with this and can tell how to be?
this is how i get the values...

$delivery_day = $this->request->post['delivery_day'];
      $this->session->data['delivery_day'] = $delivery_day ;

Answer 1

after checkout, all session variables should be reset. unset() for all session variables after order confirmation. and nothing can be said from your 2 lines of code