CallHero uses feature called Conditional Call Forwarding to receive your rejected calls and connect you to our system.
You need to make sure your US Cellular plan includes the call forwarding feature.
I have Call Forwarding
1. Disable your phone's Wi-Fi connection.
2. Open your phone's dialer, dial *90*5512027253 and press the send button.
Note: Press the dismiss button when a notification appears on your phone. If the message states call forwarding activation was a success then you are done. If it failed redial the activation code.
3. Go back to the app and try to activate the service.