This month, the OVO website wouldn't let me enter meter readings. I called them yesterday to say it still wasn't working, still no statement generated for January and still no £66 payment been made this month.
The girl on the phone was very helpful, took the readings. The online system is having some sort of major issue, apparently. Hope it gets sorted out soon - I don't want to have to change supplier again. Leaving Scottish Power was just a ball-ache.