Shell energy broadband - any feedback from recent joiners ?

I signed up to their Superfast Fibre and Landline deal, via MSE link, for £31.99/mth, with promotional reduction of £9/mth and £75 bill credit to be paid on or about 31st December. I have a welcome email from them, dated 18th Sep 2019, that has all these salient details and that also contains a summary box of charges at the bottom that explicitly states that (excluding any call costs), the total monthly charges will be £22.99. In brackets below this figure is the all-important phrase: this includes VAT.
My service went live on 3rd October.
Imagine my unpleasant surprise when I received my first bill to discover that, for the period 3rd October to 8th November, they had charged me £27.59 which, itemised, consisted of £22.99 for my package and £4.60 VAT! By my own calculations, because the period was for longer than a calendar month, the total should actually have been £27.64, so I am 5p up on the deal. At the moment!
I called their customer services and was speaking to them for 15 minutes, trying to explain my problem with the VAT, but he wouldn't listen to the point I was trying to make. "I've been 2 years in this job, I know what I'm talking about", he said. Well, tell me this, then, sunshine: why does your supposed clear-as-a-bell, itemised bill fail to show the charges broken down into (a) a service charge for a calendar month plus 6 days, VAT excluded and (b) the VAT for the same period? You've charged me, as far as I can tell, the flat monthly fee of £22.99 inclusive of VAT, PLUS an additional VAT charge of another 20%. The additional 6 days you seem to have forgotten about!
Like I said, I'm currently 5p up on the deal by my reckoning, but my confidence that it will remain that way over the next 12 months has gone into hibernation if they can't see my issue with that.
Oh, and the itemised bill didn't become visible unless I first viewed the email in my browser and then clicked on the link "View My Bill" embedded in that page. A direct Login to my account would only show a summary bill. Yes, very simple billing indeed!

Lizard king, I think they are charging you £28 a month. What price were you expecting?

I based this on £28 for one month plus £4.60 for the extra four days. But it is hard to be sure what price the four days are based on.

I agree it is sneaky that you will end up paying 18 or 12 months at the discounted price but also an extra four days at the undiscounted price. But it is pennies in the end I guess.

So it's a bit of a guesstimate, was I close to something that makes sense?(

Recently signed up for the Shell deal and the speed seems to be OK. Previously with Sky based NowTV. I've found there isn't much to choose between suppliers. Customer service with Shell is very poor, but they have sorted out one problem and promised to sort another. It's just a pain to have to keep chasing and repeating the requests.

I was tempted to go with this deal - it's incredibly cheap - but when I had a gas and electricity account with Shell Energy their CS was appalling and, judging by comments on here, their broadband CS isn't much better.

I think I'll pay more and avoid the hassle.