Calcutta Electric Supply Corporation [CESC] — excessive amount of bill unlike previous month

Address:

Shyambazar 5 point crossing

I have got the electric bill of july which shows an amount of 1170 where as in june it was 840 and in may it was only 510! I can't understand how it can be possible to rise of almost 2 times within less then 60 days? I have not bought any of electronic goods in last one and half year. You can cross verify my bills if you want, i have all the bills as a proof of my complaint.