To get reviews from your customers you can use your existing email service. Try a few of your customers first to see how many respond and how quickly they respond.
You want to create a steady flow of feedback/testimonials (whatever you call them).
You can create an email and send it to multiple customers at the same time without everyone seeing that the email was sent to other people. It will appear that it was an email sent only to them. See images for instructions below:
And it works for Gmail and most other email services.