I have a current subscription to "Bitdefender Total Security - 5 Devices" that will expire soon. I purchased a new activation code from Amazon, but when I enter it on the My Subscriptions page and click Activate, the only option is to "Add a new subscription". The activation code I purchased is for the identical product, "Bitdefender Total Security - 5 Devices". Can someone please tell me why this code does not allow me to extend my existing subscription? Thank you.