To rule out the obvious: Do you experience the connection issues on both US and EU entry points?
A few months back, I had the same problem as you. But since patch 423 (released mid september) I've maybe experience 1 or 2 disconnects. Reading you still experience these connection issues, IT COULD be the case that it's on your end. Because a problem what is still current, is that 3DXChat needs a very stable internet connection, and it not able to "buffer". When you lose a few packets, the client will disconnect you.
Things you can try:
Do the self test here: https://3dxchat-statu