Luiz,
Thank you for your advice.

During the time when both we and the bank thought it had been a wire transfer of funds, we asked the bank if they could just send it back or refuse it whatever. They said they could not do that. And that is kind of ridiculous, because how can you be forced to accept money you do not want? What you said makes a lot more sense. We will remember that, if something similar ever happens in the future.