Accidentally bought a subscription and funds were debited, how do I get them back???

I still can’t figure out how people accidentally make purchases. You have to confirm that you want to make the purchase every time that you buy something.

In any event, you will have to cancel the subscription first.

See or cancel your subscriptions - Apple Support

After you cancel, you can try to request a refund.

Request a refund for apps or content that you bought from Apple - Apple Support

You can also request a refund for a recent renewal of an in-app subscription.purchase