go to the change subscription option and see if you can see this new promotion plan. I knew some people can't see this deal somehow. I just did the switch from 34 for 20GB to 34 to 40GB on my next renewal date.
I can't log on my account last night. However, I just tried this morning and it worked. I can see the black Friday $34 for 40 GB @ 5G deal and just did switch to it from $34/20GB plan.