Question (in settings the "messages" option disappeared)

Hey all I just found this forum and i seen a lot of people helping others with there issues well this is my issue I repair phones mainly iPhones I disabled my iMessage and the iMessage on te iPhone 4's I was refurbishing today and well I put my sim back into my phone and for some odd reason in settings the "messages" option disappeared i don't know of there's a way of getting it back or not can someone help me out? I am using a factory unlocked iPhone 4s jailbroken on 5.0.1 if this helps thanks.

 

Honestly I have no idea thats why I'm asking I turned off iMessage just like anyone else can do and it's just gone? Weird.