Sometimes it is necessary to manually remove an app using the powershell
here is how to do this
In order to remove an app package you need to have the full package name
you can use the get-appxpackage command to get the full name
for example if your app package has the name MyApp in it enter
get-appxpackage -name *MyApp*
you will get all the information on your app package. look for the line that says: PackageFullName
then enter
remove-appxpackage fullNameOfPackageHere -confirm