i would just pretend to be going along with them but don't actually answer anything, if they ask, for instance, what you favourite colour is, say, well that depends on lots of thing, and start rambling about how you like certain colours for your clothes, and others for your bedroom and then on nice days you like flowery colours and on overcast days you like others and just go on and on waffling at him
tell him you are looking through your diary to find out which colours you chose most over a year and say you're counting them ...
start shouting up the stairs, shouting "BERRRTTT... what would you say was my favourite colour? because i like pastels don't i... but also darks... oooh yes good point, i hadnt thought of neons... i like those... but only in small amounts... i know, where is that wallpaper sample book we had? ... well you must know, you had it last! well next time put it away, you're always doing this, losing everything" ... then have a big row with someone they cant hear ... just basically be a pain.
or if you aren't very good at ad libbing, just say you are getting a pen or something an leave the phone on the side for 10 mins
i have kept some of those eejits trying to access my computer on the phone for a good half hour at times, pretending i have a really crap slow computer and i really need their help - i say i am turning it on, and then i say its running a chkdisk, which i cant stop ... they wait and wait - even phoning me back a few times to see if its done when theyd had enough. haha
or - if its only 2 questions - just answer them - but give daft wrong answers