Your Message Could Not Be Delivered - Cut Vendor

Hi guys,

I have a problem, I want to cut contact between customer and vendor (CS Cart Multivendor) in case they want to do business behind me. Sadly if there is any problem with customers e-mail they send an email with customers data, for example:

If you do so, please include this problem report. You can
delete your own text from the attached returned message.
               The mail system host xxxxxx said: 421
service temporarily
unavailable (in reply to DATA command

How can I delete this option for vendor. I want only inform admin about any issue with order or email or provider.