After you send a message, you'll see 'sent', 'delivered' and 'seen' depending on what happens to the message next. Here's how it works:
The message has left your device.
The message has been received on your Connection's device.
Your Connection has opened the message.
If you're still unsure or you think something buggy's going on, please contact our Support Team and describe the issue in detail. Any illustrative screenshots are good too: sometimes, an unresponsive Connection can look like a bug and vice versa, so the more proof you can share with us, the more our dev team have to go on when investigating.