Purchasing apps within Toca Boca

Have loaded the Toca Boca app and am attempting to purchase items from within the app - the first purchase was successfull but the second attempt to purchase an in app item was unsuccessful and the message “your purchase could not be completed. For assistance contact iTunes support at www etc. is someone able to assist. I have more than enough credit on my Apple gift card and the rest of the app seems to be functioning?