Naturalistics review for Seguno Email Marketing

It's a great app. But does not update your subscription email list. They asked me if my customers opp for email marketing? I have 1500 customers that did noy get updated to their app when added to my store via csv file. my customers now from 1754, to 3000 don't get emails. So I have to update weekly on Shopify. So keep on top of these in Shopify!!! It's a lot of work.