@mismi,
Hey Mis... just seen this...
I would go with not answering too... but I understand what you're saying.
If you are getting worried hun - first up - talk to the Professor and let him know that you are concerned. Would be good if he could pick up the phone when it rings... that would stop anything in it's tracks ... if that's your concern, which I think it is.
Talk to the Professor and then call the phone company sweet girl.
Else, you 'aint gonna stop worrying.
Could just be that whoever is on the end of the phone can't hear you talking, but you can hear them. Try not to worry Mis, but do tell the Professor. K?