You have a phone. You know only three people know the number.
During a meal, the phone rings. It is none of the three people, it is a telemarketer trying to sell replacement doors and windows for your house.
Do you:
a) Put the phone down.
b) Politely decline the offer and put the phone down.
c) Say something witty like "Ok, give me your home number, and I'll phone you at your home at a time convenient to me and we'll discuss it"
d) Launch into a Mister Angry rant about how you haven't actually got a house, am not likely to have a house in the near future because of the injustice of life, how did they get this number and did their mother have carnal relations with a donkey in order to produce such a colossal ass? Then feel guilty and give them The Ex's number, assuring them that she would be overjoyed to hear about new windows and doors.
In my defence, I am still a little upset about the whole apartment thing. My father and aunt gave me a round of applause when I returned to the table.
