SMITH&SMITH review for Mailchimp Email SMS Marketing

I can't rate the App yet because despite following every instruction (i was previously linking straight from Shopify-Mailchimp), and despit ShopSync saying everything is linked, and despite Mailchimp saying 'everything is working okay', I still cant get the mailchimp subscribe pop up box campaign to appear on my site. I don't mind teething issues installing Apps, but the service response time is really poor, as is the quality of the replies. I would have expected to be able to chat in real time, but only email with 2-3 day lag is possible. I was expecting - given you have to pay for their service option, that someone would have volunteered to jump in to my Shopify stiore, to review code, and fix for me. As is, service has been really really poor. I'm giving them another 48 hours to resolve otherwise I'll find another solution. I'll provide an update here if/when I get one.