Not sure what you tried, but they haven't fixed the problem. I just tried 100 different random 6-digit passwords using a python script over a one minute interval, then logged in to my account just fine using the web interface.
I'd post my code, but that would let any idiot figure out how to replicate this attack. Try including a user agent, and not using the same cookies every time.
I really hope that Virgin are not stupid enough to go after you in some lawyery way over this. I think you are already running a risk by disclosing this at all. The usual next step when a company doesn't show willingness to fix a security problem is that they try and shoot the messenger :-(
I'd post my code, but that would let any idiot figure out how to replicate this attack. Try including a user agent, and not using the same cookies every time.