Calcutta Electric Supply Corporation [CESC] — reading taken after 37 days of previous reading date.

Dear sir, today your a employee came to my premises for noting down the reading of my electric consumption after 37 days of previous reading. It means excess 6 days reading will be included into this month's bill with the highest rate slab of the bill. That means i have to pay more than normal.
This is a objectionable bad practice for which your customers like me are pressurised to pay more than normal.
Please prepare my electric consumption bill of 31 days and add the excess 6 days bill to my next month's bill. You can calculate the bill on average basis. Thank you.