SC Line item Deletion

HI

I am working on classic scenario SRM 5.0; follow on document is Purchase Order in backend

One of user has deleted the line item of SC after the PO, confirmation and invoice, Status of SC is deleted.

Because daily he is receiving mails that SC is rejected, please edit it

Is it possible to reject shopping card after confirmation and invoice once created and if so then how to stop rejection mail

Regards

Madhuvanti