I'm with Tiscali and found there support to be very poor, when I emailed then they did reply reasonably quickly, a couple of days, but in my case they seemed to lack the ability to read as the reply they sent had nothing at all to do with what I asked.
I ended up phoning them on 0870 744 2922 and of course got the usual Indian call centre (eventually) where they showed their great inepness yet again but they did eventually sort it out. Took 3 phones calls lasting 15-20 minutes each time but at least the phone number is national rate and not peak rate.
Personally my connection has been reasonable. I just ran the Tiscali connection check click here and I get anything between 600 and 850 kbps.