If you log onto the online account manager, you can see your call information. There is no fee for incoming calls, no matter where they come from. They only deduct from your plan minutes.
You will need to contact AT&T customer support with the phone information as to why you and your sister cannot connect. This is a user to user forum and that information cannot be answered here.
You will need to contact AT&T customer support with the phone information as to why you and your sister cannot connect. This is a user to user forum and that information cannot be answered here.