How they charge for helpline..mobile companies?

hi

i just dialed 111 on my jazz to help line and then after one ring the recording began ,ya call 2 rs jama tax ka hisab sa ,,bla bbla bla,,' ,, as i wanted to talk to a customer numainda to ask them for mnp,, but realizing i may need balance later,, i just disconected,, and instantly i got an sms stating my balance has droped below 3.5 and is 3.4,, heck i was charged rs above 2,, dont they chagre only when we talk to numainda? its dishonest,,,

how others charge for help line?