Complaining about a high bill on a customer to customer forum won’t reduce it 😜
Are you still in contract? If you signed up over 12 months ago then the discounted rate has finished as it’s not a lifetime deal.
Have a nosy at this link which explains about the first price increase to broadband in a few years.
Is that what you are referring to? If so use the final drop down to get a number and call the team.
Otherwise make sure you’re signed in and you can call the number from the link.