how do i call a cell phone in australia?

[Bret L]

i am trying to call from my verizon phone,i have the intl calling plan,...they heve a service called telestra.but when i call i get a msg due to events beyond our control your call cannot be completed at this time.i am using all of the proper codes..plus i cant text them i can only reply to theres and theres will only go thru if its a pic text..thanks.