First of all, this custom component applies primarily to the residents of Russian Federation.
Here I present a custom component I did in one night after I failed to submit my electricity information to the Mosenergosbyt website, hence losing a few bucks due to a rounded electricity bill.
The sensors so far are pretty basic: once you configure your own platform, at least two sensors will pop up, one matching your account information, and another (or multiple) for metering equipment set up at your home. It does not collect any information directly from the devices, however it polls your personal cabinet for latest indications submission, days left to submit them, etc.
Services to submit meter values (to integrate with home automation) are in active development. I am trying to figure out edge cases to make these sensors more future-proof, such as:
- Multiple meters (gas/power) for one account
- Different meter tariffs (single, dual, triple, etc.)
- Outstanding invoices
- Long-term unpaid invoices and notifications
In the nearest updates the following will be added:
- Services to submit indications
- Notifications about upcoming payment periods (some information is already embedded in the meter sensor
Suggestions are welcome, as I am very new to this. 
GitHub repository:
https://github.com/alryaz/hass-mosenergosbyt