Most disputed electricity bills in India come from a handful of causes: an estimated or average reading followed by a large catch-up bill, a meter that runs fast or has stopped, a jump into a higher slab because two months were billed together, a sanctioned load penalty, an unexpected FPPAS, or a landlord or society charging a private per-unit rate. Cooking gas problems are usually about refill delays, overcharging at delivery, subsidy not credited or safety.
The Electricity Act, 2003 gives every consumer a defined route. You complain first to the DISCOM in writing, then to the Consumer Grievance Redressal Forum (CGRF) set up under Section 42(5), and if still unhappy to the Electricity Ombudsman under Section 42(6). The Electricity (Rights of Consumers) Rules, 2020 add rights on metering, billing and compensation. For LPG you go to the distributor, the oil company's grievance system, and for wider service problems the National Consumer Helpline.
Start with how to complain to the CGRF and Electricity Ombudsman. This is general information, not legal advice; for theft or unauthorised-use assessments under Sections 126 or 135, speak to an advocate.