Are companies permitted to lie about the terms of a contract over the phone or by webchat?

Back in May (2022) I agreed to subscribe to a 24-month broadband contract with Vodafone for £20 a month.  Crucially, I only agreed to this as I was assured the price would stay at £20.  Given the inflation rate, that made it reasonable value.  Here is a screenshot of that assurance (I've covered up her name).

It's not very clear, so I reproduce below:

Vodafone: you can get up to 70.5 Mbps download speed,

Download speed 38 Mbps to 70.5 Mbps Minimum guaranteed 35 Mbps 

Upload speed 10 Mbps to 18.4 Mbps

Vodafone: 24 month contract :)

Me: 24 months! Can you not make it 12 months? Also is the £20 price guaranteed, or might it go up during those 24 months? 

Me: Just grabbing a coffee, be 1 min 

Vodafone: we dont do 12 month contracts for broad band, only 24 months and no the price will stay £20 through out the 24 months, there will be no price increase at all :) 

Also, when I received the confirmation email, it said:

So that satisfies me since it implies that it will not increase before that 24-month period has elapsed, not even to keep up with inflation.

However, I've just read a telegraph article.  It refers to BT broadband bills increasing by somewhat more than inflation.  It says:

It puts BT at risk of a clash with the industry watchdog Ofcom, which is preparing to take action on misleading small-print charges.

At that point, I became concerned and did a search for Vodafone's small-print terms and conditions.  I found the following.

So, if I'm interpreting this correctly, the £20 charge will be increasing by inflation plus an additional 3.9% charge!  So this directly contradicts what I was told via webchat.  And clearly, I would never have agreed to the contract if I had been aware that I had been misinformed.

Are companies permitted to lie to people about the price they will pay?  Surely not?  Or is the law even more of an ass than I originally thought?