Thanks for posting and welcome to the community. Sorry to hear you're having issues with the emails.
Please can you check your IP address here - https://mxtoolbox.com/blacklists.aspx - to see if it's blacklisted? If it's listed as blacklisted, you'll need to perform virus and security scans using your choice of security software, and once it's no longer triggering the spam systems the IP address will be removed from the blacklist.
If you're not on one of the above blacklists or the issue remains after performing the necessary checks on your devices, please head to https://netreport.virginmedia.com/netreport/ and complete the relevant form which can be found by selecting "Email Sending Errors" from the dropdown menu.