A lot of time it happens that you call a foreign country number from Singapore without adding appropriate carrier IDD code, for example 019 for SingTel, and at the end of the call you realize that your balance has vanished. This app will check your outgoing call number and will block the call if it doesn't have appropriate carrier IDD prefixed.
Add + to numbers to watch, so it will watch all numbers starting with +
Add +65 to numbers Except to exclude +65 from the numbers to watch.
Also add appropriate Telecom provider's code so that the app can remind you of the correct code when it blocks a call.
Valuable feedback are welcome.