I fergot to enjoy the cash back in my first electricity bill .how do I enjoy it in the second bill? Describe or guide me on mob 9879457879

Sir actullay i added 20 rupees but i can able to pay via online mode

i am also freecharge user, its very easy faster way to use in less time. the customer care number helped me lot. thanks for sharing sir.
http://www.techgalatta.xyz/2018/10/amazon-customer-service-number.html

Mera balance refund nhi huva he