Why is the global accelerator already deleted and still charging？

Hello.

It seems that you will be charged until it is deleted, so if it has been deleted successfully, I don't think you will be charged any more.
https://aws.amazon.com/global-accelerator/pricing/?nc1=h_ls

Fixed fee: For every full or partial hour when an accelerator runs in your account, you are charged $0.025 until it is deleted.

I think it would be a good idea to check if it has been deleted just to be sure.
https://docs.aws.amazon.com/global-accelerator/latest/dg/about-accelerators.deleting.html

If you are still charged, we recommend that you open a case with AWS Support under "Account and billing".
https://docs.aws.amazon.com/awssupport/latest/user/case-management.html