As per many threads on this forum, it is scammers making these calls.
They do not have any proof you are a Virgin Media customer, they have just looked through the OFCOM number allocation database on your exchange to get the number batches allocated to each provider. They then call you pretending to be from that provider on the assumption you have not ported your number elsewhere.
The numbers they use to call you are fake, so it’s no use blocking them.
Best advice is just hang up.
Virgin BB TV Landline. Freeview/Freesat HD, Virgin Mobile, Tesco Mobile. Cable customer since 1993
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