loose your credit card, call your credit agency, get new card different number, hope for a sensible resolution with appsumo now made more likely when you have turned of the taps to your bank account.
I have blocked the card the moment I noticed it. I informed my credit card company and appsumo same day. Yet appsumo is preventing chatgeback which I think very unethical for a reputed company. It is evident that these putchases are transferred to another account and appsumo is not willing to look into it