Is it just me?

I know I gripe a lot, and I apologize to my regular readers. But this time I actually want some feedback as to whether I'm right or not.

As we were preparing to leave our old house, I knew there were the utilities to switch/cancel. BT (telephone and internet) required a phone call, so I did, and you have heard about that. The electric and the water both had online forms to fill out, so I did those. I got the electric bill in a couple of days and that was easy to take care of.

I waited for a water bill, and it didn't come. So I emailed the company to ask when the bill would come, and how much would it be (I'd called first, but it isn't a toll-free number, and I was on hold for 20 minutes when I gave up). They wrote back a few days later (their response time is 10 business days!) and said they would close the account as of the day of the email, and the amount would be X number of pounds. They also said I didn't give them a forwarding address so they would send the bill to the old house. In waiting for the response, I'd done some digging in the file cabinet and found a fact sheet or whatever from the water company. On that paper, it said that they would automatically give 20 GBP if they didn't provide me with a bill within 10 days of requesting one.

So, I answered the email and reminded them that I DID leave a forwarding address when I filled out the online form more than 10 days ago. So, I asked for the bill to be sent to me minus the 20 GBP good faith promise thing, AND I wanted the bill to reflect the original date requested in the moving form.
They wrote me back and said I never filled out a form - they didn't lose it or ignore it; I didn't do it. Therefore, the 20 GBP would not be applied, but they would be nice and bump back the date for me.

So a couple weeks later I got the bill (by the way, more than 10 days after the email). The date was bumped back by 18 days, but the amount was the same. Since they do "estimated" water usage instead of meter readings, and there is a daily "standing charge" it only seems logical to me that the amount of the bill would be based on the days of the billing period.

So I wrote them again asking for the bill to be reduced proportionally to the reduction of days billed for, plus the 20 GBP for them being so late. They wrote me back and said to ignore any previous amount I'd been quoted and just pay the most recent bill, and that I wouldn't get the 20 GBP because the created the bill within 10 days of my email.

I wrote back again explaining myself more clearly, and am waiting for a response.

Am I wrong? Their company policy says they will "provide [me] with a bill" within 10 days, or pay 20. Even without the online form, it was more than 10 (business) days from the emails to the day I got my bill. They say since they processed a bill within the 10 days they are clear of the obligation, but that is not the language in their policy.
Also the bill amount. ? The had to have "upped" the estimated water usage to make up for the lass in daily charges to make the bill end up the same amount as it had been before they changed the dates.

This is a total of 36gbp that I'm asking for. It wouldn't break them, but would make me happier.

So, is it just me? Or should Anglian Water do something here?