GST on interest on bank loan EMI

MANOJ KEDIA (48 Points)

01 July 2018  
I had purchased a product on Amazon & paid through ICICI Bank credit card under 12 months EMI option.
EMI is of Rs. 804 per month.
Bank has debited 709.25 principal + 94.22 interest +16.96 IGST @ 18% on int amt.
Is it lawful ?
As per my knowledge if bank is charging interest on late payment of credit card bill, then only bank is supposed to charge GST on this interest.
But in case of interest on loan EMI bank is not supposed to charge GST.
Please clarify.