If you want to manually remove the app code in your store theme, then please follow the steps for removing the app code manually:-

Simply Go to the Online Store > Theme > Action > Edit Code > theme.liquid > head and remove the code (   {% include 'za_country_blocker' %}  ) 

Note:-In some theme having different structure, so you need to find app code in your theme if you are still having trouble to remove the app code,  then please email to us support@zendapps.com, we will help to remove the app code.