I was having some connectivity issues with the Band's BT connection to my L1020 cycling on and off. Looking around the forums I found a number of others citing similar issues with various kinds of solutions. Soft resetting the phone fixed mine, but looking for more advice led me to this MS support page on the topic.
Troubleshoot Microsoft Band Bluetooth and sync problems | Microsoft Band won?t sync
Worth a look if you are having problems.
Troubleshoot Microsoft Band Bluetooth and sync problems | Microsoft Band won?t sync
Worth a look if you are having problems.