We do not mean to deliberately make an error which results in a credit note.
The mistakes occurred due to the constant changing of BOs and POs due to their new system and also the original BA375 was split into two POs, and the fixed service costs and at cost items were not correctly advised to me, nor was the fact that an existing PO was absorbed into the new PO which was BA375.
Can they please enter the credit note as given. Now I have the correct invoicing information and PO numbers under their new system, there should be no further errors or credit notes.