unexpected billing

Hello.

Because AWS re:Post is a community forum site, you cannot cancel payments for costs incurred in your AWS account.
If you encounter unexpected charges in your AWS account, please contact AWS Support by opening a case under "Account and billing."
Inquiries under "Account and billing" can be made free of charge.
Also, please delete unnecessary EC2.
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 contact AWS Support from the URL below.
https://console.aws.amazon.com/support

Have you actually received an invoice from AWS indicating that they will be taking payment from you? I'm just asking because you've posted this on the 17th of the month, and AWS billing sends out invoices around the 1st of the month https://repost.aws/knowledge-center/monthly-aws-billing

Your AWS bill for the previous month is finalized at the beginning of each new month

If you feel you have been erroneously billed or you wish for charges to be waived, you can log a billing support call at https://support.console.aws.amazon.com/support/home#/case/create?issueType=customer-service

• Type: Account and billing
• Service: Billing

You're correct that t2.micro EC2 instances are in scope of Free Tier, so long as your usage is under 750 hours per month and your account is less than 12 months old. After that they are chargeable.

Also, take care which Ubuntu AMI you are using, as the Ubuntu Pro AMIs are not free.

Go to https://console.aws.amazon.com/billing/home#/freetier and it will show what your Free Tier entitlements are, and how much you have used of each so far.

Advice on tracking your Free Tier usage is here https://docs.aws.amazon.com/awsaccountbilling/latest/aboutv2/tracking-free-tier-usage.html

Advice on avoiding charges in Free Tier is here https://repost.aws/knowledge-center/free-tier-charges