Appstore doesn't want to close?

I bought a new MacBook Air. Now I have a problem.

I can't close my AppStore. There's a dot in the dock under the AppStore (which means that the program is currently running). However, there's no window for the AppStore. When I click on it nothing happens and when I click on end it doesn't close.

I also can't shut down the notebook because the app store blocks the process.

What should I do?

Press CMD + Q then it will close. The shortcut can be used for all apps.

This is just a shortcut that does the same as when you press "exit". So unfortunately that didn't work either. But I did it by pressing "option" + "cmd" + "esc" and closing the program from this list, thanks for the help!

Alt cmd esc and look for the app in the list and "End immediately".