If the subscription was made online at their website, then it must be cancelled there as well as any refund. If you are unable to resolve the issue with the company directly, then your only option is to dispute the charge with your credit card company. In this case, you will not see the subscription when attempting to cancel using the method provided by Apple.
Apple is only able to cancel subscriptions or issue refunds when they are made through an in-app purchase where you will double click the side button with the amount showing on the screen followed by verification using FaceID/TouchID or passcode. To cancel the subscription:
If you want to cancel a subscription from Apple - Apple Support
And to request a refund:
Request a refund for apps or content that you bought from Apple - Apple Support
If you do not see the subscription, then it was likely done on the website.