we have got refund for 3 of our clients which were stuck since 2017.
I have now know the tricks and routes for stuck refund cases (export)
as mentioned by you - you are using two sets of invoice one for INR and tax and other for export and USD/non inr currency
now in such cases - sb005 - invoice no mismatch sb006 - egm also not filed because invoice couldn't be validated from data transmitted to icegate from gst
talk to the assitant commissioner or commissioner of respective port from where shipment was done.
send them a documents for sb005 they will process refund in next 30 days.
if you still face any problem kindly contact me at 9545556474 I'll guide you
Sir we amended invoice no. & date which is mentioned in Shipping bill this month. Let's see what happens. we already provided all supportive docs related to this to mumbai but they have no right to sanction refund other than what is system routed filling of shipping bill