Welcome to the Community.
Can you confirm if you're using the most recent version of the My Account App?
If so, do you see a button that reads ``GET MY FREE DATA`` instead of the shake to activate function?
It's important to also note that the minimum requirements for this to work is a Pulse plan and for your phone to be running either iOS 8.2 and above or Android 4.2 and above. You can check out more details about this here.
I hope this helps.