Legal advice time please

I posted about my nightmare with bulldog broadband a while ago.

The jist of it was they were, and still are to this day, sending me bills for a phone line that does not exist.
I phoned up to arrange broadband for them but the account never went live because I cancled it before the install, lost my deposit, and moved house.

Then the bills started coming in, and have been for 2 years now despite god knows how many emails and phone calls.

I left it alone and just deleted the bills as spam, they couldn't take the money (the card was cancled just in case), and they have never chased.

For some mad reason at my new address I went back to them because they were the only 8mb providers.

Guess what, today I've found out they have been charging me for two broadband lines when I only have 1.

I have 8MB Unlimited (£20 a month)
To use this I also have to rent their phone line £8 a month.

I don't normally check them as they just come out my card each month however they have now had to go to Direct Debit and can't take payment from my card.
The DD wants £38 a month.
????
I look it up.
They have added on a £10 a month 8mb Broadband line on the same account and number charging me for 2 broadband lines (one of which I dont and never have had) down the one phone line.

I've had enough.
I've send Another complaint (number 10231) and no I want to go for legal action.
These guys owe me a LOT of money and they can't be allowed to operate like this.

Anyone know where I should go and what exactly I'm going to be pushing for in terms of slapping bulldog and getting my money back?

(also does the fact that the 8mb service only ever works at about 100kb/s and drops out randomly throughout the day for 2-3 seconds at a time, just enough to kill any applications or downloads that are running, add to my case here?)

Id say Eds your man for this.