Contact Support and reference this article.  

Please include the list of suspected payments in an Excel file, to expedite the request.
  1. Payment ID
  2. Transaction amount
  3. Transaction Date
  4. Donor Name
  5. Supporter ID

In efforts to prevent fraudulent charges in the future, we highly recommend enabling CAPTCHA on all forms and events.  It is also important to ensure you have the appropriate level of security enabled on your KinteratThon or Form by enabling Credit Card Verification (CVV) and Address Verification Settings (AVS).