Thank you for your post and welcome back to our community forums. We're here to help.
I'm very sorry to hear you're getting these unwanted calls. I can confirm that is a legitimate Virgin Media contact number, however, it's also possible for a number to be spoofed. When you answer the call does the caller advise of the reason that they're making contact with you?
In regards to your preferences change, can you confirm roughly when you made that change?
he said he was virgin media, after a few seconds delay , I then hung up. I altered my preferences about 2 hrs ago. It will now take a few days to take effect. I expect I will get many more until it takes effect. What a pain.