How to be an Adult Part 2

Update: so, having seen no results for quite a while, I phoned up again, this time using the complaints extension. The problem was that the case had been transferred to another department, and we hadn't heard anything back. Luckily, they were able to merge the two accounts then and there, and within a few days, the bills were showing up as expected.

The moral is: phone through to the right people (note for the future: always ask if they can do this, and if so, what time period they'll do it in), be firm but polite and persistent, explain the situation as fully as possible, and then with a little luck, your issue may be resolved.

Of course, I still wouldn't recommend using NPower - given this mistake was the company's fault, and that their lack of communication and lack of haste in resolving it, I'm not exactly impressed.