Utility billing is complicated in ways customers feel directly: estimated reads, tariff changes mid-period, standing charges, smart meters that stopped sending data, back-billing. A good answer needs the account, the read history and the tariff from SAP IS-U, Oracle Customer Care and Billing, Kraken or Gentrack, not a generic explanation.
The regulation is about protecting people. In Great Britain, Ofgem’s rules on treating customers fairly, the Priority Services Register and limits on back-billing shape what a supplier must do. In the EU, the Electricity Directive (EU) 2019/944 sets consumer and vulnerable-customer protections that member states implement. An automated channel that resolves bills quickly but misses a customer in difficulty fails the test that matters.