Click on the "Repair" icon in the left navigation bar, then on "Refund or exchange requests".

The list of requests for refund or exchange is displayed:

To open a request, simply double click on the desired one.

This request is "not valid".

The categories in red are those containing anomalies or missing information.

By clicking on the arrow, you can open the desired category. 

The anomalies are listed on the left, the fields to be corrected are framed in red.