1) they, I now find, have a new accounting system.
2) Paper/Postal bills ceased
3) nasty demands and credit ratings ensued. Don't ask how that impacted credit card use while miles from home!
4) paper bill re-instated, allegedly
5) paper bill not arriving, go back to 3)
6) long phone calls, paper bill re-instated (allegedly) with follow-up calls & e-mails from help dept - watch this space..........
7) on-line account lock-out - e-mail address used for all communications not recognised at log-in - first indication of "New System" appears.
8) chatbot steered to real live person and.......... "we are very busy, try later"
9) when do I give up and move my custom elsewhere?

Yea, yea, direct debit. But I want to keep my local Post Office going, and well used. DD doesn't service that requirement. And I am somewhat pissed-off in several directions. Rant over, still pissed-off.