I do not recommend KeepCalling
I do not recommend KeepCalling. They start charging before the call is even connected, and the amount they charge is much higher than the credit you actually receive. In my experience, I ended up paying about 20% more than expected. It often takes several attempts to get connected, and even when the call goes through, the voice quality is sometimes poor. Overall, the service is unreliable and not worth the money.