If you’re somehow unable to access Pro features after paying, please contact us with a copy of your receipt and the email address associated with your Brainscape account, and we can get this fixed for you soon.
Note: the "locked" and "unlocked" icons on Decks in the app look very similar. Please look closely and you'll see when the icon appears "unlocked". (Yes, we will update this soon, in an eventual UI overhaul.) It's likely that you do in fact have Pro access despite the visual confusion.