Where/How do i answer EA support e-mails ?

Hey there. You should be able to view your cases at help.ea.com and respond there.

There is no response options, only close case or resume case. And in "resume case" option even if i write something in descriptions box after that it says that "This issue isn't supported by advisors" and my case never gets renewed.

Try creating a new case to let them know you can't respond. They may be able to update your existing case. We're currently looking into reports of various issues with the new help site.