#pigmanspawners

I can’t figure out how to complete this mission. Do I keep upgrading the pigman spawner until it changes to a zombie pigman spawner?

I play skyblock one of my friends lost all of our pigman spawners somehow. I was offline at the time and none of the nether items are showing up in the shop i play on Xbox. we are at island 8 and i really don't want to delete my first island can anything be done?