So the maintainer closed your issue
Hopefully the maintainer addressed your issue to your satisfaction, with a fix or assistance you needed. But what if you aren't happy with the result?
Closing an issue does not mean "talk to the hand". Many projects use issues to manage a team's workflow, and closing issues is a form of house-keeping. It's entirely possible that an issue was closed prematurely because the maintainer didn't fully comprehend your issue.
If you feel the issue was closed prematurely, you can still add comments. Adding additional context may result in the maintainer re-opening the issue.