Delhi Jal Board — too much bill

Address:

New Delhi, Delhi, 110044

Dear sir,

My k no-[protected]
I have subit my last bill on -14 jun 2016 of rs 524, on that time my outstanding was 0, now after 3 or 4 years jal board sent me bill of rs 16419, i want my monthly statement... Sirkejrival give 700 ltr water free in a day. I have not use extra 700 ltr so how can this bill is correct. I was go also at jal board office but they didnt give response