In normal circumstances, your Bank Card isn't charged until the item is dispatched. To speak to Customer Service, click on Help at the top or bottom of any Amazon page, select "Need more help?" and then "Contact Us".
Check you have actually been charged, as Amazon charge on dispatch, however card issuers reserve the money so it is available when Amazon wants it. If this is the case then it will be made available to you soon.
Subscriptions renew automatically unless cancelled. For further information click on "Help" at the top or bottom of an Amazon page and type the words Kindle Unlimited into the search box. That will provide you links to every aspect of being a Kindle Unlimited subscriber.