If these were real marketing calls from VM, then you can stop that happening by setting your communications preferences with VM so that they do not contact you with marketing phone calls (or SMS or email or mail as well if you choose).
Have you logged your mobile number with the Telephone Preference Service (TPS) which will cut out marketing calls from legitimate companies?
Can you set different ring tones for callers in your phone address book? You can easily screen calls this way and let any you don't recognise from the ring tone go to voice mail for you to screen later.
There are also various call screening apps and smartphone features which can filter calls for you or direct unknown calls straight to voicemail. You may get best information about those in the 'Virgin Mobile' section of the forums specific to your model of phone.
Wait for a VM forum team member to respond who will be able to give further advice and check your contact preferences on your account. They will do this via private message.
They normally respond in a few days.
(You might like to unmark the answer in message #2 above as helpful until your problem is fully resolved for you)