If this was urgent in anyway, I'd call those helpful people at WXC/XNet.
I noticed last night that my Panasonic wireless handset (a very basic analogue $60 model with almost no abilities), which is connected to my WXC VOIP line, has started to display Caller Id of people whose number and name I don't have written down anywhere. People I don't know.
Is this possible or am I mistaken?