The idea which you have is a two-sided business (Business from eCommerce users & eCommerce owners). For any eCommerce company to adopt your e-wallet you first have to focus on acquiring a large number of eCommerce users.
1. If you are financially strong, connect with local eCommerce startups in a small area and start giving free signup bonus for users upon using this payment gateway to order.
2. See the acquiring rate of customers & change if you see any faults in the starting strategy.
3. Also, Check the story of Paytm in India ( their business, growth)
4. Learn to be patient, it may take more than a year sometimes for companies to adopt your wallet. But do not lose hope :)