The notification email is wrong and being returned

-- url of the page with the problem -- : cognoscitiva-pt.com/shop/
-- HikaShop version -- : updated in Sep 2013
-- Joomla version -- : 1.5.22
-- Error-message(debug-mod must be tuned on) -- : "A message that you sent could not be delivered to one or more of its
recipients. This is a permanent error. The following address(es) failed:

Hello aaaaaaaaa,

A new user has registered at Cognoscitiva-PT.com.
This e-mail contains their details:

Name: xxxx
E-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.
Username: xxxx

Please do not respond to this message. It is automatically generated and is for information purposes only."

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We are having returned email on our email of the web server where the site is hosted, by notifications of new orders that are created but that are being returned.

What it seems is that the automatic notifications of the online shop are being send to an email that does not exist anymore, and then all notifications are send back to our primary email has not delivered.

"A message that you sent could not be delivered to one or more of its
recipients. This is a permanent error. The following address(es) failed:

Hello aaaaaaa,

A new user has registered at Cognoscitiva-PT.com.
This e-mail contains their details:

Name: xxxx
E-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.
Username: xxxx

Please do not respond to this message. It is automatically generated and is for information purposes only."

---

The email is always sent to the same adress, with does not exist anymore. We are revieving the non delivered notifications, to that email adress. How can we change that email to the correct ? is it in the hikashop menu or in the joomla section?

Thanks for your time