Whilst the new SIM card is now working after having my Nokia 1616 unlocked using the unlock code from the Virgin letter, the battery drains now very quickly, within a couple of days even when not using it. Previously it was good for 1-2 weeks when not in use. I am also intermittently getting the message "nsert SIM" (especially when the battery is running low) and I have to turn the phone off and on again to make it connect to the network.