Phones

We seem to have started getting nusiance phone calls at home, at around 6 or half past. I used to answer the phone by giving the last 4 digits of our phone number but I've stopped doing that. I just pick up the phone but not say anything. If I speak or say hello, the line usually goes dead, as if they don't recognise my voice.
The other night we got a phone call and it was for our son. Somebody was trying to sell him something. The other day in work I phoned the number we were given for the Print Room and got a load of adverts, someone trying to sell us printing services.