Mailchimp Email SMS Marketing

It will not allow me to give zero stars but that is what this is worth at the moment

After installing this app we have faced many issues:
1. Order not syncing as they should
2. Customers automatically being marked as "Accept Marketing" when the box is not checked in Shopify
3. A huge disconnection between Mailchimp & ShopSync. I got both on email, each pointed blame at the other.

I would not recommend installing this app as it currently does not work as expected. I have been trying to get our problems resolved but unfortunately after 4/12 Mailchimp nor ShopSync will respond. Worst customer service I have seen. Posting here I am sure there will be a response!