Vodafone — Asking me to make bill payment without bill

I ported from vodafone to Jio as their network services were very bad. After porting to Jio they started calling me and started sending emails saying I have to pay 734.87 rupees. When asked for the detailed bill they say they have already sent, I have not received any bill crom them. When asked to send the duplicate bill they say they cannot send, not sure what is the reason. Just for using 3 to 4 days after the port request will anyone charge 737.87 rupees ?. Now I got message from Jio that i need to pay vodafone the outstanding amount without which they will discontinue the services as per TRAI. How will a operator allow you to port to other operator without clear the outstanding amount. Clearly they are cheating the customers.