Hi Anankha, thank you for the additional information.
Apologies for any confusion or concern caused by the call. As you are having an issue accessing your My Virgin Media account recently it is likely the call was regarding a ticket raised for this, to ensure your access to My VM was restored. If this is the case they will have been trying to check you have access before closing the ticket as resolved.
We can certainly send you a PM to confirm a few details and confirm if the call was from our team if you would like?
Just say the word and I will send you a PM.
All the best!
Molly