I'm sure somebody from the Virgin team can help you as soon as somebody gets round to seeing your post.
I would warn you though, pretty much all landline numbers have been in circulation now for years and you may well just be surrendering one set of nuisance calls for another.
Best way to deal with nuisance calls is to but a telephone that filters invalid caller ID and numbers and also mark numbers a nuisance, however this requires caller id which Virgin charges for which makes there landline service more susceptible to these nuisance calls.
I want to change my landline telephone number because I've been receiving a lot of nuisance calls. I can't get through over the phone, so I was wondering if it's possible to get help here?
You may get an unpredictable outcome from changing your landline number. As mentioned already, numbers are reused. You may get a 'new' number which might be an ex-business number or has had nuisance call problems in the past.
In addition, many of the scam calls are generated automatically by software dialling blocks of numbers in turn, so your new number may simply be included in one of those dialling sequences. See below for a recent post where a 'new' number received nuisance calls almost as soon as it was put into use.
Assuming your nuisance calls are the general automated scam calls which everyone receives (and not something specific to you or your existing phone number) consider looking at a call screening phone or separate device such as trueCall or some of the BT phone ranges which use trueCall technology.
If you would still like to change your number, one of the VM forum team should pick this up within a week or so and should be able to assist.