
When the argument specified by the user is invalid, the app shows an error message and that should be the end of the use case and it should not resume back at step 1 as it assumes that the user will request to add a new contact to the contact list immediately after this error message.
When the argument specified by the user is invalid, the app shows an error message and that should be the end of the use case and it should not resume back at step 1 as it assumes that the user will request to add a new contact to the contact list immediately after this error message.