This is happening to me also. Not nice when you've just tried to open the bank ...
Going back to the character page is the only way to continue - just reconnect to the character you were using.
Unfortunately, this doesn't work when it freezes in a battle - when I have to shut down, and restart, hoping you are still alive and kicking when you rejoin the fight again.
Typing /ping when you first realize guild chat has stopped may get you a pong (hopefully in low numbers) followed by lines of chat from everyone, or it stalls and it's time to relog. The highest pong so far was a massive 683095ms.
I've checked out my router and modem which are working fine. I can view forums with no problems during the freezing, but even without anything else running I will still get the freeze.
I've tried reducing the graphics, putting everything to minimum, clearing the cache ;p almost everything I can think of, and still it happens.
I've also noticed that if left running, despite being frozen, it stays up. Since the update I have never seen "Disconnected due to inactivity".