Here is their last answer :
"Unfortunately, if the payment email/account selected has an issue, please contact the payment provider to address this issue. This is your responsibility to make sure that payment selections made by you are secure and safe to use to receive payment, and we cannot reimburse missing payments in cases like this.
As per our website terms, which govern both our contributor and client sites, Under the Registration Data and Account Security provision sections e and f: In consideration of your use of the Site, you agree to (e) accept all responsibility for any activities that occur under your account, including but not limited to, all applicable taxes and any applicable third-party fees (including but not limited to credit card fees, foreign exchange fees and cross border fees); and (f) accept all risks of unauthorized access to the Registration Data and any other information you provide to Company."
The best is : "This is your responsibility to make sure that payment selections made by you are secure and safe"
=> Payment selections were precisely not made by me, because as you may know you genius iStock, your site is not safe and secure at all.