gst rule 96(10) - Goods and Services Tax - GST

we received the goods from the foreign customer for the job work purposes under advance authorisation . After completion of the job work we sent (export) it back to our customer after charging the job charges . we cleared this transaction under gst as with payment of tax option on job work charges and also got the refund of gst. Now the department is asking to pay the gst refund granted to us as this is hited by GST rule 96(10) . Can you please guide me on whether rule 96(10) of GST Act is applicable or not.