You are right to be cautious when receiving contact from people who may be unscrupulous.
We do have a number of staff members working from home at present (myself included), however I cannot say in certainty that the sales department would be contacting customers. . . . .
I am curious, Ed. My employer provides communication services and our employees working from home have an app that means if they make outgoing calls, it is routed through our company switchboard. No cost to the employee, and any recipient using caller ID sees our company number, not some private number. Why isn't a large communications corporation such as VM doing the same for your employees?
Thanks for bringing this to our attention, I wouldn't be able to confirm whether this is a genuine call or not without checking your account. I will send you a private message now so we can investigate this further, please reply when you can.