The higher charge could be because the promotional price for the membership ended and you were charged the regular price after the renewal.
If you subscribe to a trial version of Adobe Stock, the trial moves to a paid bundled pack after the trial period. Check your Plans & products page to view the products and services you are currently subscribed to.
If you have an Adobe Stock membership, you can download Standard images per your subscription terms. Any premium images you purchase are charged separately. Check the order history on your Plans & Products page to see if you purchased any premium images from Adobe Stock.
If you have an Adobe Stock membership, you might have been charged a fee if you purchased images beyond your monthly plan allotment.
If the membership price in your region change recently, the updated charges are reflected in your bill. You would have received an email communication from Adobe in advance about any price changes. You can also check the membership price on your Plans & products page.