Keep getting error message , contact iTunes support when trying to purchase items in Dragonvale. This is happening on my iPad but still able to on my iPhone.

It will quite possibly work on other devices as it could be flagged on just a single particular device, it's not necessarily done just by account, but you will need to do as the message says and contact iTunes Support and ask them for help : http://www.apple.com/support/itunes/contact/ - click on Contact iTunes Store Support on the right-hand side of the page, then Purchases, Billing & Redemption