Server disconnected/connection error

Hello!

 I'm constantly getting connection errors and disconnections from the server on my Xbox. At the time of the game's release and during the beta, it worked fine, but on Sunday evening I started having problem with matchmaking — I was being connected to Chinese servers — and now for two days I haven't been able to play. Either it doesn't connect to the server, or it kicks me out after 2–3 minutes of gameplay. I've tried connecting directly to the router and to the modem, using a wired internet connection, opening ports on the router for Xbox, restarting both the router and the modem, and even changing the DNS, but nothing has helped.

How can I solve this problem?