request for refund since i believe my account was hacked

Hello.

If you encounter unexpected charges in AWS, you should open a case with AWS Support under "Account and billing".
https://docs.aws.amazon.com/awsaccountbilling/latest/aboutv2/checklistforunwantedcharges.html

For questions about your AWS bills or to appeal your charges, contact AWS Support to address your inquiries immediately. To get help, see Getting help with your bills and payments. To understand your bills page contents, see Using the Bills page to understand your monthly charges and invoice.

You can inquire by signing in to your AWS account and using the URL below.
https://console.aws.amazon.com/support

By the way, I think it would be a good idea to provide AWS Support with CloudTrail logs, etc. to prove that your AWS account may have been compromised.
I think the following documents will be helpful in what to do if your AWS account is compromised.
https://repost.aws/knowledge-center/potential-account-compromise