Redeemed a 3-month prepaid Live card, now not showing up?

Hey there Jack! I apologize about that problem. Have you checked
http://billing.microsoft.com/ to see what happened? If not, please do so and make sure all your payment information is up to date. If you continue to experience this problem, please reach out to Xbox Phone Support so they can have a look at your billing
information and get it sorted out for you.

Time you redeem via prepaid cards is fully added to whatever time is left on your son's account (up to 36 months).

So for example if your son has still 3 months of Gold left on his account, and you add a 12 month card, your son has 15 months of gold on his account.

Or if your son has an active subscription, and his subscription would renew in 3 months from now, and you add the 12 month card, the prepaid card will "pause" his subscription, activate 12 months, and after the 12 months of the card are over, the subscription
will continue with the remaining 3 months, and your son will have to be billed again in 15 months from now.

So there really is no need to wait until you redeem prepaid cards.

In fact, since some promotional cards have an expiry date on them, I heartily recommend to redeem prepaid cards as soon as possible.

But keep in mind, that you can have only up to 36 month of Gold or Game Pass time on your account.

yes, you still have the 12 months since it's a prepaid card. Plus, you can also redeem it now since xbox live gold subscriptions can be stacked up to 36 months.

Indeed, token stacking works on a recent-first basis. The most recent membership you purchase or redeem is what is consumed first. If you have 3 weeks remaining on a 12-Month membership, and you redeem a 3-Month prepaid card, then after 3 months, those
remaining 3 weeks kick back in and it's business as usual. Peculiarly, if you have a 1-Month membership set to auto-renew, and you redeem a prepaid code, it will turn off automatic renewal. In other cases, if you had a renewing membership, but you turned
off auto-renewal, and you then redeem a prepaid card, this can turn your auto-renewal back on, as the prepaid card tells the system that you're not interested in canceling afterall. Therefore, it's always a good idea to go to Xbox.com/account after you've
set up your Gold, to make sure that the automatic renewal is in the state in which you desire it to be, on or off.

I just bought and redeemed my prepaid that I bought from my local Target store,still have the receipt for said card

my three months originally ended on the 7th of this month but I redeemed my 3 month gold for live on the 1/3/2014 an inputted the code to renew my xbox live...and it said the code went through but now I am without gold an hour early before midnight .

not a happy xbox user