Hello FarahRamzy,
It sounds as though you were charged for a subscription you canceled through the application, but noticed the subscription was still active via the App Store. Apple Support Communities is a great place for help, and we’re glad you were directed here from the How to cancel a subscription from Apple article. If the subscription was active via the App Store, that would be the likely reason you were charged for the app.
Canceling the subscription as you have via the App Store is the right step, and we're glad you were able to do that. If you’re seeking to request a refund, you would want to review the following article. It provides helpful information on how to request refunds for iTunes and App Store purchases.
Request a refund for apps or content that you bought from Apple
If you have additional questions, or need additional help with requesting a refund. You can reach out to Apple directly. Their contact details can be found via the following links.
Apple ID – Official Apple Support
Get Support – Apple
Take care!