I have been working with this service for almost 4 years now as an Agency Manager so far everything has gone smooth at all times they are always professional in their work ethic which makes them easy going people who you can trust 100%.
They also give great support when there's any issues or questions regarding our account setup etc., We use multiple channels of communication from email through messenger chat apps like WhatsApp/Skype & Facebook Messenger but we still haven't found anything negative about using these services other than maybe having more options would be nice (but not really much).