since your script already uses the API from Toon I was wondering whether you can modify it to backup the data from the energy and gas.
Since Toon on Tablet it's possible to show it through the API and with a little fiddling I got the json code. It follows the same structure as your program for as far as I know. You can make yourself immortal by creating a plugin or standalone script to backup this data

Here's an example:
<The usual login string>
https://toonopafstand.eneco.nl/toonMobi ... dChecksum=<some-checksum>
Output is json and all the data (months, weeks, days,years) is there.
This is the string for gas
https://toonopafstand.eneco.nl/toonMobi ... dChecksum=<some-checksum>
Again data is json ouput, the same as electricity.