Hi, I've read many forums on this topic but have yet to find one that solves my problem.. I bought a used iPhone off of Craigslist that was locked to AT&T so I had it jailbroken and unlocked so I could use it on T Mobile. Everything worked perfectly fine until I accidentally upgraded my IOS. The jailbreak was undone so I brought it back to the store where I got it jailbroken. They restored the jailbreak but all of a sudden iMessage was no longer working. After weeks of trying to figure out what was wrong I found out the number in My Number had reverted back to the original phone number of the phone, and iMessage was trying to use that phone number as the "send from" number. I can't change it in My Number or in iMessage because it is greyed out. I've tried turning it off and on multiple times, signing out of imessage, neither of these work. I actually can no longer even sign into iMessage, it just says "waiting for activation" and never goes anywhere The only thing I have not tried is reinstalling IOS which I don't want to do because then I will lose the jailbreak again (and that's what caused this to happen in the first place). Does anyone have any other suggestions on how to correct the phone number to mine?