Netflix debited despite cancellation?

I made a Netflix account with a trial month at the beginning and specified direct debit as the payment method. I canceled the contract on the same day, so I only cancel the free trial month. Now the following problem occurred: Netflix has now simply debited the 15.99 euro, I have 1. 25 days trial month and 2. Yes, actually free.

Does anyone know if they will pay the money back or something?

If it is direct debit you can cancel it with online banking

Could you explain this further?

What did Netflix support say?