How can i call a restricted number back?!!?

Question

i know for a fact that it is possible because i once prank called a friend and he called me right back and was like ur phone number mite be blocked but i know how to call you back...he moved so i cant ask him and i need help...[[[nobody is harrasing me o i dont need to call the cops about this]]]

Answer 1

*82

or

*69

Answer 2

I wish I knew.