@revk I've never understood how energy suppliers manage to make simple calculations so hard to follow. I've previously spent ages trying to figure out why my accounts don't match the supplier's statement, only to find out that its because they quietly replaced an old statement (same dates, different figures). Luckily I had already downloaded it so I could compare the old and new PDFs for that date (shouldn't changing a statement after you've issued it be illegal?)

@revk When I had a dispute with nPower it became impossible to work out what was owed because each statement ended up being "corrected" (with more incorrectness) about 5 or 6 times. So I ended up with 5 or 6 different statements for each month over an 18 month period, with no way to know which was the latest "correction".

@steve I have two cases with the ombudsman. One relates to a £14k re-invoiced for whole time I was with them (#bulb), issued 2 years after I left - not even allowed by OFGEM rules as it means back dated more than a year. And they are using a starting reading that is thousands of pounds worth different to actual starting reading. I don't understand how they are so bad at this, especially "hand over" readings, even when smart meter present!

@revk Well, nPower spent the whole time insisting that the whole thing was my fault. Ombudsman told them to stop screwing around and pay me a big lump of compensation for my troubles. Which they eventually did (not within the required time scales). About 6 months later, out of the blue nPower compensated *all* their customers (including me) because the thing that was "my fault" turned out to have happened to the majority of their customers and the ombudsman had told them to compensate everyone.

@revk Essentially, nPower had stopped bothering to collect a direct debit. It was all set up, they just stopped using it for no good reason. I didn't notice because they never sent me any bills. It all came to light when I suddenly got a debt collector's letter for 18 month's worth of energy, to be paid within 28 days. Apparently this was all my fault because I should have noticed the DD not being collected. They wouldn't take responsibility for not collecting it and not sending statements.

@steve We bill phone calls, and data usage, and all sorts, and manage that with emailed itemised invoices, on-line accounts, proper DD notices meeting the requirements. These energy companies typically sell two things, gas and electricity, and have meter readings to do it. It is about as simple as it could be, and they seem to be really good at getting it very wrong. It is quite amazing really.

@revk Yeah, I really like the A&A bills - dead easy to understand. I've not had you make any mistakes on my bills, but presumably you would just issue a second bill with a "correction" line item subtracting out the mistake, rather than re-issuing the bill you already sent?