I cannot figure how the phone and the account with Call with Us work together, allowing me to make (and receive) in-country phone calls. And I read that I should drop to the $5 plan while out of the country, since there should be plenty of free Wifi in Israel.
Have you set up your CallWithUs account to work with CSipSimple - Android Apps on Google Play as outlined here: Adding International Calling to Your Republic Phone | Republic Wireless Wiki | Fandom powered by Wikia. If so, it should simply be a matter of dialing the number you wish to call. If that’s not working with the native dialer, are you receiving any error messages. If you dial a call using CSipSimple’s dialer (bypassing the native dialer), does that work?
Your Republic phone receives calls from anywhere, so you won’t be using CSipSimple and CallWithUs to receive calls only to make them. You’ll need a data connection on the phone (WiFi for example) for this to work.
It would also help the Community best help you, if we knew which Republic phone you have.