Hi and welcome to the Forum.
Not sure I can assist with the busy tone your caller is getting, but one quick thing to check regarding this.... have you yourself tried to call your Blackberry from say a landline to hear this yourself?
Secondly, regarding the no ringtone..... click on "Profiles" option and check what the active profile is.... then scroll through the list to pick one that suitsand click on it.
Hope this helps... if not, please sing out and one of our experts will assist further