Now, here comes 18% GST. This is a tax on your ENTIRE transaction of Rs.1000/-, and not just on that Rs.2/- Zebpay fee. So, you now pay Rs.180/- GST.
Do you have any confirmation on this? I am pretty sure that exchanges will charge GST on the service that they provide (or exchange fees). Charging GST on the entire transaction does not make sense.
https://www.zebpay.com/fees/This talks about 0.2% fees on transactions and 18% GST.