Support
GoodWin VPN is a client for a configuration you import. It does not sell a Goodwin proxy or an account.
Who to contact
Write to the operator who gave you the subscription URL or share link. They run the node your device connects to.
In the app
Settings → About → Support opens this page. Open-source licenses for bundled libraries are in Settings → About → Licenses.
Privacy
How the app uses VPN, camera, and on-device secrets is described in the privacy policy. Privacy.