Invalid item pop to stop the trasaction

We are implementing SAP Customer Check Out for leading hypermarket Company in Mena region

Below scenario we are unable to achieve on Customer Check Out

Scenario :

If item are not available on SAP Customer Check out

Reason 1 : Barcode may not scan properly supplier barcode print issue

Reason 2 : Item not synchronized from ERP system

In this case in a retail rash counter cashier will have customer more than 5 to 10 in Que with more than 30 Qty of items & cashier will not notice that invalid items notification which is correctly run and items will add to customers list without billing

As per current scenario cashier are not noticing items are available or barcode scanned correctly or not.

Workaround recommending :

A setting require for sales "invalid items what to stop the transaction" , If Yes it can stop the transaction

This can bring cashier attention ,item can bring back & avoid this item from sales or look into the issue and solve.

I would appreciate if you can provide a workaround to solve this issue.

Please find attached screenshot for your reference.