Now that the Credit Card Payment is set you might wanna go through the rest of setting within the Woocommerce Plugin and adjust to your wishes. A lot can be customized.

I also tried to refund within the WooCommerce Plugin and it worked perfectly!

Here is the link:

https://docs.woocommerce.com/document/woocommerce-refunds/

I hope this helped and I wish you great fun with your very own online store :)

Kind regards,

Tina