my bill was paid and amzon is requiring me more bill

I understand your concern about unexpected charges on your AWS account. As a student using AWS for class assignments, it's important to be aware of potential costs. Here's what you can do:

1. First, make sure to delete all resources you've used to prevent further charges.

2. You can request a refund by contacting AWS Billing Support directly. To do this, you need to open a support case under "Account and Billing" in the AWS Support Center. This type of support is free of charge.

3. When creating the support case, provide detailed information about your situation. Explain that you're a student, used AWS for class assignments, and were unaware of the charges. Include any relevant information from your instructor about expected costs or free usage.

4. If possible, gather evidence of your student status and course requirements to support your case.

5. AWS Support will review your request and guide you through the refund process if applicable.

6. For future use, familiarize yourself with the AWS Free Tier and its limitations. Also, consider using the AWS Pricing Calculator to estimate costs before using services.

7. If you no longer plan to use AWS, you may want to consider closing your account to prevent any future unexpected charges.

Remember, while AWS does offer a Free Tier for many services, some usage may still incur charges. It's always important to monitor your usage and understand the pricing for the services you're using.
Sources
How to get refund | AWS re:Post
How do I get refunded for this embarrassment of a product? | AWS re:Post
please refund a bill,bill ID: 1792774229 | AWS re:Post
please refund a bill,bill ID is | AWS re:Post