Just got another letter...
I already got a letter last year saying I had to choose a new contract, so I followed the instructions in the letter, to the letter, and chose a plan with AYCE data and 30GB tethering for £18 a month.
They completely ignored this request and I remained on my old plan.
This new letter gives me the option to move to a plan with 1GB data for £5 less, or 4GB data for £2 less. I'm not best impressed that they ignored my initial choice and have now moved the goal-posts and given me two inferior choices!!
Nevertheless, I rarely use more than about 2GB data, so I chose the 4GB data plan...
This is the first time after years of being a Three customer that they have ****** me off. I'm sure it was just some error or other though and I can't be bothered to go into a store and kick up a fuss about it...