Dear Menghok BUN,
Welcome to Microsoft Q&A.
Thank you for sharing your situation. I am very sorry for the double billing that you have communicated to us. I understand your frustration, and we will work together to resolve this case.
First of all, please help me check your order history on https://account.microsoft.com/services
If the charge has doubled, you can follow this link to request cancellation and request a refund. Cancel a Microsoft 365 subscription
How to get a refund for a Microsoft subscription.
If the above steps haven't worked, for your security and privacy, the last option is to contact Microsoft support. Please help me confirm your situation so that I can provide you with the necessary instructions for contacting Microsoft Support.
I hope you can resolve your case smoothly.
Kind regards,
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