re export

Export thr machinery under drawback claim as per Section 74 of the Custom Act.

Sir,

We are an 100% EOU unit, We have exported our materials to our foreign Buyer. Due to quality problem He had rejected the same. I had taken back (imported) the goods,by under Execution of Bond in Customs , With the standing Condition that " THE GOODS WILL BE RE-EXPORTED WITHIN 6MONTHS TIME".   

In the mean time buyer had made the payment to me.  He had not raised any debit note to me. Now I could not return the materials to the customer. So i like to pay duty for the imported goods.

My question is , Whether the duty has to be paid along with interest,  If so what is the present duty calculation and whether i  can take the credit of customs duty for DTA sale .