Driver didn't accept cash on delivery

A week ago I ordered items worth 500 Rs. on blinkit and it was COD but the moment my delivery arrived he insisted on paying online instead of cash and worst part was he was deaf, so I didn't understand what he was trying to say.

Since my parents went to bangalore for two days they gave me 3000 Rs. for food and other necessary items and I don't have UPI and I couldn't call them either as they had already boarded flight.

Even after repeatedly convincing he wasn't able to understand finally I had to ask my neighbour to pay online.

My question is why wasn't he accepting Cash despite me opting for it??