Hi guys I used bsnl since 4 years many things changes now they are providing great network covrage areas in many states also they are making step towards rural areas.there are 24/7 customer service from bsnl.they are providing many attaractive packs for customer.the packs they provided are better than other operator like jio and idea, hence I think currently they are best with customer support and charges and billing section hope you also use it.
thank you