Company error do I still pay?

[kittylitter7]

I recently received a letter from Tiscali (my ISP of over five years) stating that they do not hold any valid payment details for me.
I found this very strange as my service has never been affected in any way.
The letter then went on to say that the last payment they received from me was in October 2005 and therefore I owed them �431.76!
As I have quite a few direct debits and the Tiscali DD is still live on my bank acct I didn't realise or even think to check if the monthly payment (�15.99) was being deducted from my account each month.
I simply do not have this kind of money and I feel it is Tiscali's error for A: losing my details and B: not recognising the fact for well over two years.
Can anyone please tell me what my rights are regarding a situation like this please?

[funnygirl]

Are you sure this is a genuine email from Tiscali and not a phising email???

[kittylitter7]

It is not an email, it is a letter and I phoned them so I know it's genuine.

[bednobs]

i am basing this answer on my opinion, not my (very small) legal knowledge.
You have had the benefit of the service, yet have not paid for it. I think they are more than entitled to ask you for the money, however i believe you could negotiate terms ie you'll pay 5 pound a month.
learn a lesson to look at you statements i guess!

[Postdog]

Got here late but isn't the obvious thing to do is check whether money actually left your account, and if so, find out where it went. If your bank was paying it out, it must have gone somewhere.