Hi @Nahyun ! Celine from the Community Support team at Figma here, thanks for reaching out! I was able to see your support case and have added a follow-up note internally to increase its visibility. For reference, your case number is 1991516.
Our Support team will review your invoice, verify what caused the unexpected charge, and get back to you as soon as possible. When you have a chance, please keep an eye on your inbox for their reply. Thanks for your patience!
Update: The agent has resolved your issue, please check your inbox when you can.
For others who may running into similar issues, of you'd like to prevent additional charges in the future, we recommend using seat approval settings to automatically manage new seat requests. This setting will require Admin approval for a user to be upgraded to a paid seat. Our Help Center article provides step-by-step instructions on how to change the setting. I’ll go ahead and close the topic here!