When receiving an error the system was unable to add the following items - ...(item not available for return), this happens when you enter part of a customer account code in the customer search box (top left corner). If you have multiple accounts that partly share the same account code e.g. AM1001 and AM1010, if you only enter AM1 then Prima does not know which account you are trying to return the goods against.
To return the goods, you are required to enter the full account code/ company name.