i worked in 2 call centres when i was 16. dont worry, iv come to my senses now and hav a proper job. anyways, it realy isnt the fault of the caller, u shouldnt go crazy at the person on the other end of the phone - they dont call you, it is an automatic calling system that goes through a PC using software called Amcat or Touchstar.
it really is a rubbish job to hav because you only get to work if theres a place for you at the start of every shift, and this is the same for most call centres across britain. the reason so many youngsters work there is because they pay stupid amounts of money for such a small amount of work... i was earning �18 for every 3 hour shift i worked and a fiver for bonuses on top of that.
for college kids that realy is a gud income because they arnt paying bills yet, and they are getting upward of �120 per week.
in answer to the original question - ring the telephone preference service (TPS) and register. if you still get calls then jus say 'im on the TPS' and they will b sure to leave you alone because thay can get sacked or fined if you complain...