There are commercial products that claim to do this by intercepting calls and only allowing through those on your approved list. Expensive and not always seen to work.
And if you think about it how does a telco know whether a call is a nuisance call or not? You'd have to answer it to know that. And in most cases the calls come from spoofed numbers here and abroad which change all the time so no chance of keeping up with that.
Don't change your number. All VM numbers are recycled now and are still bound to be on spammers lists.
TPS is the best bet. But spammers and scammers have ways round that too. There is no perfect solution to this.
VM can't block the number. If it is a single caller with malicious intent talk to the police. That kind of behaviour is a crime. But will you get anywhere? Doubt it. All the help that exists is in the link I gave you.
As a Very Insightful Person, I'm here to share my knowledge. I don't work for Virgin Media.