19% Price Hike in less than 1 year

[#1]

I took out the 12 month line rental in November last year paying £155.88. I received an email from Plusnet today saying that prices were increasing to .. £185.88 which is a price hike of just over 19% !! How can plusnet justify this as CPI inflation is near zero? 

[#2]

mod:note
topic already under discussion here https://community.plus.net/forum/index.php/topic,140995.0.html, so this one is locked