We are having an issue with spark where one person has the phone icon on the chat screen and can call the other person and voice chat just fine, but the second person does not have the phone icon in the chat window and cannot make any calls.
Were you able to fix this problem? I am having the exact same issue myself and cannot determine why. I have the little phone icon myself and others do not... I can call them and they can converse via pc mic and speakers but they cannot call me since they lack the little phone icon. Does anyone have any insight into this?