Can you confirm that you do not have trouble delivering similar order confirmation and dispatch emails to large professional email providers such as Gmail, Yahoo!, AOL, etc.?
I'm sorry to say that there is a long history of problems with delivery of legitimate emails to Virgin Media accounts since August 2015. Virgin Media moved from Google-hosted mail to a Dovecot system with an OX App Suite front end with Cloudmark filtering run by Liberty Global in the Netherlands beginning in the summer of 2015 and have been struggling dramatically with delivery and spam problems ever since. Here is a partial list of complaints and reports,
When you do receive a resolution, please come back to the board and let us know how the problem was resolved. Many of these cases since August 2015 lack information about how and if the problem was solved. Such information would benefit other senders who will find themselves having to file similar reports on this board since Virgin Media lacks more appropriate contact methods, documentation, and self-help discovery tools for commercial senders.
Before you jump to conclusions at to what the problem is - you should at least get specific information about the error codes. Note that Virgin Media changed what happens to inbound mail - so that in most cases Senders should not be getting the old Spam Content found errors - unless a specific user has changed their email settings again.
I do want to see this problem solved, because from a number of threads it looks as if the problem is down to greylisting rather than outright rejections. But I'm not jumping to conclusions without gathering more information, as to do so does not help senders or recipients.
Only use Helpful answer if your problems been solved.