Dear Mrs ******
The issue is not what you were told but what the contract that you entered into allows the provider to do.
It is not sufficient to simply say that you were informed of the price rise. A price rise cannot be imposed on you without your agreement unless the agreement that you signs enables the provider to raise the price. The same applies to the term of the agreement, if you agreed 12 months it remains 12 months, So unless you were mistaken about the length of the term it cannot be changed unless the agreement expressly permits it
You should ask for copies of the e mails he is referring to and ask him to identify under which clause in the contract the price was raised and the term changed.
If he can actually produce these then you will have to pay but can do so in instalments. I would send a letter saying that you can only afford to pay it off in instalments and enclose the first instalment. You need to make it a reasonable amount , say, £20.00.
I hope this helps. If there are any further points please reply I will be happy to respond.