@galactus said
I play mainly on the app and i cant seem to read or reply to a final message from my opponent also in the app if I miss replying in a chat box I can't find a way to message them whilst it's their turn. Any solutions would be greatly appreciated
From the three bars at the top of the app you should find a 'My Messages' link.
That's where you can send out-of-game messages. Click the plus icon and start typing the players name - it should start giving you a list of suggested recipients.
The last-chat message in a game will be there, but the opportunity to respond is with a move - so if the game's finished, so has the chat with that game.
I think the links that take you to the end of a game put you to the board history, rather than the game itself, that's why the messages are not visible.
Maybe a site suggestion to allow in-game chats to continue and for the "your game has ended" links to take you to the board where you can see those last messages.