Meghbela Broadband — incorrect billing amount collected

Address:

Kolkata, Kolkata, West Bengal, 700124

I am using a connection of meghbela broadband from march 2016 through an local operator. During april 2019 it came to my knowledge that they are collecting excess amount from me by submitting false hand written bills and upon asking for the bills with gst details... They are denying to provide the same... I am chasing meghbela office at kolkata for last 20 days over mail and phone.. But they are not cooperating... I want my excess amount to be refunded and appropriate bills with gst to be submitted to me by meghbela.