Your VPS is responding just fine. You can verify this by navigating to any external ping service such as http://ping.pe or https://network-tools.com/
It sounds like this is an issue with your local ISP / 高墙 being unable to connect to your server IP, and in that case it is unfortunately not something that we can change or control.
We can change your VPS IP for a one-time administrative fee of $2.99, however please note there is no way we can guarantee connectivity between our network and the 高墙 even after an IP change.
Please let me know if you would like to proceed with me sending you the invoice for the VPS IP change, or if you would like to keep it the way it is.