Very common problem. Take a look at some of the other posts on this subject. I received three devices and none of them provided sleep cycle data.
Two of them still didn't work after completing all the required customer service troubleshooting steps, so they were returned. I am still working with customer service on the third one.
You should work with customer service to see if they can get your device to work. Some people have had limited success doing that.
Good Luck!
