Black box saying "Optus" on my home screen when locked

All of a sudden a black box has appeared on my locked home screen showing my phone provider "Optus" - its very big and annoying when I am trying to view any notifications... plus I just don't want it there. I have tried changing the wallpaper to see if goes away but it wont. Can anyone help me please - very Ugly!

[Edited by Moderator]