Don't know how to cancel services

There is a good guide on identifying services that you want to shut down here: https://aws.amazon.com/premiumsupport/knowledge-center/check-for-active-resources/

Once identified, you can use the following guide for details on how to terminate them: https://aws.amazon.com/premiumsupport/knowledge-center/terminate-resources-account-closure/

Specifically for Amazon Elastic Compute Cloud (EC2) you can use the AWS Console to view any current instances you have configured by searching for and selecting EC2. As EC2 is regional, you will need to confirm you have no instances in any region - you can use the EC2 Global view to get a quick overview. In the screenshot below you can see that there is one instance configured in Europe (Ireland) eu-west-1.

If you click on this number, you will get a link to the instances which will include resource ID links you can click on to allow you to manage the instance and from here you can click the Instance State button and choose Terminate Instance to shut down any unwanted resources so you are not billed.

For a full set of steps to follow to ensure all services relating to EC2 are terminate see here: https://aws.amazon.com/premiumsupport/knowledge-center/delete-terminate-ec2#Delete_or_terminate_EC2_resources

Amazon CloudWatch collects metrics and data from your other AWS services so once all other services are terminated no additional data or logs should be generated. You can then delete any existing Log Groups from the AWS Console by going to CloudWatch > Log Groups > Select log groups > Actions > Delete log group(s).

After you have completed all of the above I would advise closing your AWS account entirely which you can do by following this guide (you can always re-open a new account if you need one at a later date): https://aws.amazon.com/premiumsupport/knowledge-center/close-aws-account/

NOTE: There is a 90-day period after closing an account during which any non-terminated services may continue to accrue charges so ensure you have carried out the above steps first.