Issues are "bad" ratings which need to be resolved with unsatisfied customers. Bad ratings are related to Goals, where you can set which values you consider bad. How to set value for bad ratings.
Issues overview gives everything you need to now before you act. See the value of the ratings, customer name and comment.
When you use integrations with ticketing system you can even get back to a problem ticket. Afterwards you can take actions, resolve or ignore the issue.