I dont know where it is written that the price of being born is you have to take a phone call from your mother every sunday morning at ten.

Also, not taking their phone calls does NOT make then die sooner. If only! if anything, i think they hang on longer just for spite.

I recommend telling them the truth - these phone calls just now are interfering with you making your way in the world. You will contact them to make arrangements for the next holiday. Then start screening your calls.