Vu: " I've just registered account to dispute, got email confirmation said account is registered, yet I cannot log in at all..............."
I don't know what CSC's problem is with registrations, I always have the same problem you describe too. But it's easy to get around....
Click where it says "lost password?" on the page you get after the login fails. Enter the requested info and they will Email you a password that will work within 10-15 minutes. (They say 1 hour, but in my experience it happens faster.)
The page where you register at CSC does say your registration will only be valid to use for 48 hours.... So you do have to go through the motions all over again when you return later.
All in all, I find CSC the easiest of the 3 CRAs with which to work. But that's actually due to more demerits on EX and TU, than a feather in their cap.