Blackbell lets you collect ratings from customers on products / services they have purchased from you. 

24h after the service is rendered, an email is sent to your customer, asking him to review his experience. 

Customer can submit his rating from the application. He can also add a review. 

All ratings & reviews can be found under the "Ratings" section of your admin interface. 

You can choose to display for some or all of your services the average ratings received by verified customers.
Display the average notation of the service as well at the number of collected ratings.

To do so, go to E-Commerce > Manage > Setup > Customers Ratings, and select which ratings you wish to display. Reviews will remain confidential .