Changing Premium for Family accounts

[shashar]

I had a Premium for Family account which I just cancelled because another family member already has a Premium for Family account for me to join and emailed me a invitation with a redemption code. I can't find anywhere to redeem the code, the redeem page says code invaild. I clicked the link in the email but it just takes me to the payment & subscription page with no space to enter the code.  The support page says "You can only switch from one Family plan to another once every 12 months.".. could that be why I can't redeem?? I have never been on another family account before.