I used to be able to go to settings and hold down the account and choose unregister. Now when I do that, all I get is the option to delete the account. How do we unregister the account? It is driving me crazy that my mobile phone is answering my business calls and my business phone can't take them because they keep going over to zoiper instead. I want to be able to control which phone answers by unregistering zoiper when I don't want it to answer calls, and then register it when I do want zoiper to answer calls.
Just expand the settings -> tap on your account -> and tap on the green checkmark, this should unregister your account.
You can also add the Zoiper widget to your home screen and use to quickly register/ unregister your account.