Very disappointing experience.
I installed Rebtel because I needed to call Denmark while I was in Indonesia. The app indicated that I was making calls through Rebtel, so I naturally assumed the calls were being handled by their service. What the app didn't clearly tell me was that it was routing the calls through my Danish mobile operator instead. As a result, I have now been charged approximately 700 DKK in unexpected calling charges from my supplier. Rebtel's explanation is that I should have enabled "Travel Mode." My issue isn't that Travel Mode exists, it's that the app never gave me a clear warning before placing the calls through my mobile carrier. There was no obvious message saying something like: "This call will be placed through your mobile operator and may incur roaming charges." Had I seen that warning, I would never have placed the calls, nor used their service. Their customers service, wont take responsibility for this, and is not interested in taking ownership of this obvious bug. I will report this to App Store, and I suggest everyone reading this does too. Im sure this voids Apple's ToS.