If you have no network connectivity but you have verified your VPS is up and running according to the control panel then please do the following.
1. Click the reconfigure networking button in the VPS control panel.
2. Run the following command: touch /option.netfilter
Your VPS will self reboot within 30 minutes and that should resolve any issues, please do not manually reboot to try and speed this up, that will cause it to completely fail.