I got my Series 3 with LTE on Friday. I am on a Unlimited Plus plan with AT&T. I talked to a really nice girl on Saturday at AT&T, and she double checked all the inputs on their end, and said all was correct. She said she would call me back today, because they were having issues with the system being overloaded. I still haven't heard from her. I am finally getting to the screen on my Apple Watch app on my iPhone, where it lets me log into AT&T, and then it takes me to the "activate your device" screen, where it lists my current data plan and also says I will be charged $10 additional per month. IT DOESN'T go past this point. I've tried turning power off and on on both devices to no avail. Can someone give me some insight into what my next step should be? Thank you!!!!