Mailchimp Email SMS Marketing

We've had many teething issues getting the Mailchimp app functioning and many of them still aren't working as they should. I've spoken with Rhedd at length today (for over an hour) and their service was 5*. They tried their best to help, and forwarded me onto their developers for additional support. My review is mainly of Rhedd's service as our issues are still on going (hence the dropped star).
Hopefully the developer are as helpful as Rhedd and the issues we are having get sorted.