All customers’ feedbacks are registered in the Customer feedback section in the store's Admin area (Orders -> Customer feedback):
To manage a feedback click the […] button opposite the feedback in question. You’ll be redirected to the Manage Customer Feedback page where you can check the survey details and the comments provided by the customer.
Each feedback except for the ‘excellent’ ones get the NEW status that you can change to ‘IN PROGRESS’ or ‘CLOSED’ when the feedback is processed. The ‘excellent’ feedbacks get the CLOSED status automatically.
To process the feedback further you can contact customers by email to thank them for the feedback left or to help in case of any questions.