eway gst

As I m manufacturer of namkeen nd we supply our products to the remote area as approx 100km from our factory in our own vehicles.(goods value more than 50000)
we send our vehicles for sale it's ready stock sale and we sell our product to approx 50 different customer in different areas in a day without any pre order from our customers
and most of the time some quantity of the goods came back to the factory so how can we generate eway bill as we don't have pre orders for our goods and even our salesman are not capable to cut the bill calculating all taxes on the spot.