Paying twice in a month usually means one of the following:
Your payment for the previous month was delayed and didn't go through, so it was postponed until it was possible to make the charge.
You're paying for two accounts.
We suggest that you check your bank statement as well as your receipts on your account page to see if you have any charge for the last month. If you don't, it's most likely that the payment was postponed, and a couple of days later you were charged for that month's subscription.
If this is not the case, and you were actually charged in November, we suggest that you check out this help article to find other accounts, and this one for more info about paying more than once.
Hope that helps, and let us know if there's anything else!
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