Sometimes customers might want to modify their own bad reviews. For example, after a resolution has been made or if the complaint is not related to the product, among other things. If a review was submitted in response to a review invitation via an aggregated review form, the customer can modify their review using the same link from the original invitation. Please ask them to click the "Review" link in the email one more time and update their review.
If a customer cannot find the original review reminder (invitation), it is possible to re-send them the review reminder. Re-sending of review reminders is available in the Pro version of the plugin. Unfortunately, it is not possible to re-send review reminders with the Free version because of the limit of one reminder per order (see this article for more information).