If you purchased a retail copy of OneCare from an online seller, the boxed copy contains a PIN or retail key on an orange sticker on the back of the CD tray - 25 digits - that is used to activate your subscription.
There is no 3 year renewal, it is one subscription for up to 3 computers for 12 months.
If OneCare is installed on your PC and in trial or expired mode, it needs to be activated with a LiveID and the PIN/Key or payment information.
If you purchased a 12 month subscription online from Microsoft with a credit card, you simply need to install the trial from http://onecare.live.com and then subscribe, signing in with the *same* LiveID used to purchase the subscription. If you are being asked for a key or payment, you are using a different LiveID than the one for your purchase.
You can verify if you have an active subscription for a LiveID by signing in at https://billing.microsoft.com
I can't speak for why you were unable to get through to support, but I deleted the phone number from your post as this is a publicly visible forum and the support number is valid only for subscribers.
You should be able to call the number you have (if you are in North America) and speak with support, not just leave a message.
-steve
