Problem making purchase from asset store

I just tried to make a purchase from the asset store (web not in-app) and got a red response saying there was a problem with the transaction and I should contact support. First: how? Second, I contacted my credit card company (fraud detection has had issues with Unity purchases in the past) but they said not only had the transaction gone through, it had gone through twice. (They cancelled one of the transactions.) I've since visited the in-app store and it does not show the item as being purchased.