“You” cancelled your subscription. “You” renewed it. Netflix gladly charged you
It doesn’t matter that “you” in this case is the owner of the CC and their mother. “You” purchased a month of netflix and got it.
And on the off chance your credit card company DID just give you the money back and penalize netflix without asking any questions? Then this becomes fraud and netflix have good lawyers AND would love to put the fear of god into account sharers.