I was wrong to put gold prepaid card

The only option is to set your xbox as home xbox in order to share gold with the other account.

Gold is not transferable but you can share gold in this case, as Denis said

you can gameshare with your second account but unfortunately it will not be able to be un redeemed, and unfortunately from the forums no one can access your account this would need to be done via support.

If you don't have much time that movement was made you could talk with technical support to see if they can help you otherwise put that account as the main Xbox so you can access the multiplayer without problem

Not possible, you would have to set the account you put gold on as your home xbox to use it... always double check the account you are trying to redeem things to make sure it is the right account in the future.