Delhi Jal Board — Bill received 3000 rupee

Hi sir, my name is deepak and live in A1/13 gali no.1, raja puri uttam nagar. My K.No. is [protected]. sir i shifted here one year before and that time here no where water supply and we used summer well water. now i got my receipt of water connection and i paid water bill 650 of may. sir i have 500 ltr. water storage tank and water supply once in a day in evening. now i received a bill of 3000/- of june. i dont know how to do because 20k water is free and i consumed 15k because my water tank capacity 500 ltr. please help me of this bill issue and resolved this issue sir. please help me. Deepak [protected]