four sisters were at centre of an international custody dispute .
the girls were sent back to live with their father in italy in 2012 .
they were dragged kicking and screaming from their sunshine coast home .
the distressing scenes shown on tv caused hysteria and concern .
60 minutes has exclusively interviewed the girls at their home near florence .
their mother has not visited them in italy until now .
this edition of 60 minutes will screen nationally on channel 9 at 8.30 pm this sunday , april 12 .