I wanted to buy a Shadow egg but when I Filled it out, it said that the transaction wasn't completed.
Can you please make sure the payment method you are using is not expired or out of funds (if its like a gift card or something)? If you're using some sort of gift card, make sure you register it with the provider in order to use it. Other than that, just make sure you are entering all your correct information with no mistakes.. If it still doesn't work, try a different payment method.