Hi there @hotbroccoli
Thank you so much for your post and welcome to the community forums, it's great to have you here.
I am so sorry to hear that you are facing issues updating your number in My Virgin Media, we are aware of some customers facing this issue but the number does still show as updated on our side.
I'd be happy to check this for you via a PM, I'll pop one across now. Please keep an eye out for the purple envelope in the top right corner of your screen alerting you to a new message.