You will see they say that if you save the sender as a contact in your Webmail account that will stop their emails being flagged as spam. However, there is a massive caveat to that.
In many cases VM flag emails as spam not because of the email's content but because of the results of the checks they have run to confirm the email has come from the sender that appears in the "From " field. That is to prevent so called email spoofing that is a trick used by spammers and scammers to make emails appear to come from a legitimate source rather than a spammer / scammer.
If those checks give VM cause for concern as to the email's authenticity then those sender's emails will always be flagged as spam in your Webmail account. Even turning spam filtering of altogether will not prevent that.
I'm a Very Insightful Person, I'm here to share knowledge, I don't work for Virgin Media. Learn more
Have I helped? Click Mark as Helpful Answer or use Kudos to say thanks
Wait for the forum team to reach your post in a few hours / days to help with resolving the false positive.
In the meantime consider trying the following to try and identify the cause:
repeat the previous instruction to send the problem email to yourself instead but this time highlight half of the message body, cut to clipboard by pressing Ctrl + X and then send the email
If the sent email is delivered into your: ➱ Spam folder, reply to it but before sending highlight half of the message body and save to clipboard by pressing Ctrl + X ➱ Inbox folder, reply to it but before sending highlight all the message body and paste previously save clipboard by pressing Ctrl + V to overwrite it
repeat the previous step until the problem part of the message is identified