Query for accounting treatment

I wan to know the treatment of following situation.

I sold soods of rs. 100,000 to government co.

Amount approved by them is rs 97000. than how should i treat the balance 3000 rs and what should be entry if at time of sale following entry is passed.

Govt. Co. a/c    dr.  100,000

   To , Sales a/c           100,000

which head should i use for treating rs 3000 remember it is not a discount.