Calcutta Electric Supply Corporation [CESC] — unbelievable billing even after 7 days of no supply, post amphan.

Dear sir,
The current bill i received from cesc is unbelievable. It shows a consumption of 864 units. Never in my consumption history, i have seen such a high bill. There was no one who came for taking meter reading since lockdown 1. The bills generated were assumed values. This current bill for may 2020 shows an unbelievable amount of rs. 8140.
I have not added any gadget for electricity consumption recently as, all shops were even under lockdown. Above all there was atleast 7 days of power supply failure, post amphan cyclone.
I really suspect some unscrupulous practice in this matter. Please review the situation & send me a believable valued fresh bill for payment.
I am attaching screenshot of previous bill summaries, generated from your cesc app, for ready reference.
Regards,
Indra nath bagchi
Consumer no: [protected]