Tds default

One of my client has received a default notice for short deduction of TDS. The client has received a certificate issued U/s 197 from Seller of the Property (who is NRI) for lower TDS rate. The same is correctly provided in the ETDS return for short deduction. However, CPC has not considered the Certificate and issued a demand for differenial tax. Now as all data in correct in the ETDS return, what is the solutions to nullify the demand.

Please suggest......