My Skillbuilder Subscription was cancelled but I am still being charged

I recently sought and obtained my first AWS Certification. To train for it, I signed up for Skill Builder in early December only to find out a few weeks later that my company already offers this free to its employees, so I (thought I) cancelled it.

Evidently, I failed because I was charged the monthly fee on January 1st, so I found my mistake and the indication was that I would have access to the resources through the end of January and my subscription would be cancelled at that time.

Nonetheless, my credit card was charged on February 1st for the monthly fee, so I reached out to the people here: https://support.aws.amazon.com/#/contacts/aws-training

The result of that (CASE ***************) was this:

Thank you for contacting AWS Training & Certification.

To cancel your AWS Skill Builder subscription, do the following:

1. Log in to AWS Skill Builder: skillbuilder.aws
2. In the menu, choose My Account.
3. Choose Purchases and Subscriptions.
4. Choose Go to your subscriptions.
5. Select Cancel Subscription, and follow the prompts.

Best regards, Razieq J. Amazon Web Services

I followed the above instructions and responded that there was nothing there to cancel, which was confirmed by the rep:

Hi Jonathan,

Upon review of your account, I was unable to locate any active subscription as it says your Subscription has been Cancelled on Jan 31, 2024.

If you're still being charged, please reach to the AWS Console Support team. Due to security policies, they can only assist account holders via a support case. Please use the link below to submit a support case:

https://console.aws.amazon.com/support

You will be connected with the AWS Billing and Accounts team, who will be able to assist you further.

Best regards, RINKY D. Amazon Web Services

And yet I'm still being charged. I want a refund for the February payment and assurance that I will not be charged on March 1st.

Because I'm on the free tier, I have no access to phone support and the support link above just brings me here.

How does this get fixed?

*Edit: Removed case ID — Dino C.