Suppose I have purchased goods of 10 units(raw materials or semi-finished goods) worth Rs10000 from vendor A (suppose) and also made payment for the same. Now during the manufacturing process, it was observed that 3 units are defective, now my question is how do we deal with the defective units in SAP as I have already made payment for the 10 units(i.e Rs10000).

Answer: If you have a GRN against these materials, then the same can be return delivered. An appropriate movement type needs to be configured for the same. As for the payment, raise a credit note on the vendor.

* Using Debit Memo you can get the money for defective 3 units.