Can you use the same club penguin membership card twice?
If your Club Penguin Membership Card said this, there could be a glitch. No worries, try emailing Club Penguin and explain the problem, Club Penguin may ask you a few questions (what is the code for your card?...) so just be patient and double check to make sure that you have never used this membership card.
The year membership on club penguin is $57.95. You only have to pay once. The 6 membership is $29.95 and the one month membership is $5.95. They sell membership cards at many stores where you can buy a 1 or 6 month membership, and then enter the code on club penguin, (using the instructions on the back of the card).</