> - how do you get a new bank card, when the current one expires?

The bank sends it through mail but they warn you that if it doesn't arrive within 2 weeks you should go in person to the bank to retrieve it. Depending on where you live there's a 50/50 chance that it never arrives through mail so you just wait 2 weeks and go to the bank.

> - how are you informed about a change like a price increase for electricity?

Email. Or the news channel for elderly people (if the increase is too big). If the increase is small that's a fact of life, everyone just expects it to increase a bit every 2 or 3 months.

> - how do you pay for electricity? (Knowing how much to pay, when etc) What about an elderly person?

Website or bank app. There are physical places that take cash payments and do the online process for you, elderly people generally use those.