Talk Talk advice

Moosehead_2

Hi. Long time listener, first time caller (or the modern equivalent anyway). Hoping someone might be able to give me some advice following a situation with the truly awful Talk Talk.

I recently changed my bank account (following articles on this site I might add). Despite the new direct debit being set up in time, TT attempted to take money for my April bill from my old account which was of course bounced by my old bank. I spoke to TT on the phone (how long does it take to get through to someone??) and was told that the outstanding amount would be added to my May bill. OK I thought - except for the fact that they'd slapped on a fine which they would not remove despite it being their fault.

The next thing I know is that today I receive a Final Demand. This threatens that they're going to pass my details to a debt collector and that my credit rating may already be affected by non-payment of bills! I've had no contact from them asking for money since my phone call to them over a month ago when I was assured it had been sorted. I've just spoken to their credit department and it turns out that they didn't take any money in May either and so I owe two months' bills. Rather than pay for three months in June I simply paid the outstanding amount on my card today.

Naturally I was fuming as all of this has been their mistake and made this clear to them on the phone. I asked for a grovelling letter to apologise for the threats they've made but now I'm unsure how to progress.

1. Has my credit rating been affected by this and how can I sort it considering I am not at fault and their complete incompetence is to blame?
2. Can I use this as grounds to cancel my contract with them? They've been awful since the beginning (poor broadband connection, awful customer service - ie the usual)
3. I was intending to email them, cc'ing Ofcom and Watchdog. Is there any point? What's the best way to approach a complaint?

Apologies for the length of this and thanks in advance for any advice people can provide.