If you have Voxofon application installed on your device there is an option to set Voxofon application to handle all your international calls. If the option is turned ON whenever you enter an international number on your native keypad on device and hit "Call" > Voxofon app will appear letting you perform calls via Voxofon application.
Please follow the steps to enable to disable the option:
1, Login to your Voxofon account on device
2, Press on hard "Menu" key and choose "Account and Settings"
3, Open "Settings" section from Account and Settings page
4, Navigate to "Handle Int'l Calls" and check the check box
Now if you close the application, open native dial-pad and enter an international number (make sure to enter code with plus "+" and correct country code) Voxofon application will appear with already entered number.
If you would like Voxofon to perform calls automatically you can set "Auto Calling" option ON as well. Please follow the steps.
1, Press on hard "Menu" key and choose "Account and Settings"
2, Open "Settings" section from Account and Settings page
3, Navigate to "Auto Calling" and check the check box
Now Voxofon app will not ask you to use Voxofon or not, it will initiate the call automatically if you enter an international contact on native keypad and hit Call.