Just for a little bit of balance, in the summer I emailed PX to tell them that although I had ordered 2 tyres, they had in fact just put one in the box. I got a response within 2 hours saying they would look into it and to expect an answer within 24 hours. Next day I got another email saying they had consulted the warehouse, found the error and would send out another tyre that day, which they did.
On the other hand I am still waiting for a response from my complaint to Hope made by email and phone) going back to 2003. Got bored chasing them in the end! (To be fair it was a pretty trivial issue).