If one of your customers asks you to delete or export their data, go to the customer record and use Export Data or Delete Customer under the Privacy section.
Deleting a customer removes their contact details and feedback history permanently; it cannot be undone and does not affect a review already posted publicly on Google, since that's controlled by the customer's own Google account.
Sadakom retains anonymized, aggregate metrics (counts, ratings) for reporting even after a customer record is deleted.