How to enable Log in Two Step Verification from Google Authenticator on Ebay?

[cryptomogul]

I can't seem to find a way to add two step verification via google authenticator when logging into my Ebay account. I'm concerned about the log in vulnerabilities this site has considering everywhere else I shop online, and also social neteworks I'm able to protect my account from unauthorized access or key loggers, phishing attacks etc. by enabling log in two step verification via either SMS, email link confirmation, or Google Authenticator. Does anyone know how to do this on ebay? I already added my phone number under text message, but it only worked the first time and after that is not asking me to verify my log in when accessing my Ebay account. Please advise, Chris.