They have an email address for non-customers in the post I linked to as well, perhaps you can use that.
If you can use a different DNS resolver, I’d recommend doing that. While written for a different reason, the advice in this article may help:
You can also try using a VPN as @anon95807532 suggested above. Unfortunately, if you cannot switch from or reach out to Virgin Media, I don’t think there’s much else you can do.