I have had the same problems. Only after many phonecalls asking to cancel, they said they would but it never happened. I then cancelled my Direct Debit thinking that my Tiscali account had been closed. A few days later i get a letter notifying me that i cancelled my Direct Debit. I wrote back explaining that i cancelled and had not used their service for months. I received no reply. Another invoice was sent to me a month or so later, i again wrote back and received a reply yesterday. They took more than two months cancelling my account :(
Thankfully i only have £20.00 to pay off.