I did everything that I can to make a complaints to the Telewest, and they finally got back to me. They actually told me that the upgrade is DONE. And it was done very some time ago...
I have never EVER experienced any speed increase for 4mb connection. The fastest speed I experienced is 100kbs download speed on 5:00 am. If I was supposed to get the 4mb download speed during non-peak time, I think I was supposed to get faster download speed.
anyway, they told me that they are working on the upgrades , because they did not expect the traffic to increase so much... dho... and they can't actually do nothing about the problem I was experiencing until the end of March.
Instead, they offered me a refund until end of March for my internet connection. While this does not sort out my problem of not being able to use the internet for god knows how long, I won't be paying for such a **** service.
I just wish I could leave them and be with some other company.