You can contact support and see if they can help you: https://support.avast.com/en-us/contact/
Usually, the support can take a few days to handle your situation. Please, keep it in mind.

About “Open VPN config file”, unfortunately, Avast does not provide this method of authentication. We’re forced to use their software to connect to any server.
This is something that they really should work on it.

Good luck! :wink: