What is "Market 2/3 charge" on my bill?

[#1]

Hi there,
I have an extra "Market 2/3 charge" of £19.99 on my bill. I can't see any explanation what that is. What is it for?
I am already annoyed that what was a "reputable" provider should use the sneaky price increases during an 18 month contract (which I though was fixed price) that mobile providers use. This is an easy way to ruin your reputation.
Richard

[#2]

That sounds like you were on a deal of an 18 month contract with a discount for the first 12 months. Now that has expired you will be paying the full price.

[#3]

Deleted wrong!

[#4]

Hi retsof2001,
I've had a look at your bills and you've always paid £19.99 for the Fibre service. The reason your bill this month is more expensive than previous months is because of the call charges you've incurred.
Sorry for any confusion caused though