Incorrectly billed for using AWS Sagemaker Canvas

Hi, I created a free tier AWS account to learn more about the services in January 2024. In February 2024, I did attempt to create a Sagemaker instance. But this attempt was unsuccessful so then I deleted all Sagemaker instances immediately. I did not use any Sagemaker services at all, and yet I was charged $779.58 for the month of February, and the cost is continuing to accumulate for March 2024 with $11.40. The billing statement shows that it's charging me for using Sagemaker Canvas, but this is not being used at all. I checked my account multiple times and there is no Sagemaker instance. As I have not used this service, I am requesting for a refund for the February charge and correct the current accumulating cost for March 2024 to $0.

Please advise which number I can call or email to request for this refund, otherwise I will file a dispute on this with my bank.