Eric iDEAL is just like a regular bank transfer. It gets immediately transfered to the other bank and credited to the merchant‘s/receiver‘s account. At this point, there‘s no way to get it back for the sending bank or for iDEAL. It‘s not an escrow system and also not acting as a third-party (like PayPal or Mastercard).
If you get defrauded when using iDEAL or a bank transfer as payment method then your best bet is going to your local police. Of course I would also ask both banks about more info or if they can help at all, but in most cases the money would already be somewhere else and both banks wouldn‘t be able to assist.
