Feedback requests can be found in the Feedback Requests tab in the Feedback module. Requests are divided as Incoming Requests and Outgoing Requests. When users send you a feedback request, it will be found under the Incoming Requests filter. Any feedback requests you make from others, they will be found under the Outgoing Requests filters. 

If you have sent a user a feedback request and they haven't gotten back to you, you can remind them by going to the Outgoing Requests filter and clicking the Notify button on your request. This will send the user a notification email.