frauds with consumers

Location/place: mumbai

Name of company/service: mtnl(dolphin)

my bobile no is 9869407613
last 2 months without sending sms or taking any services i had been chrged for ISD sms to the folling numbers
527270099 – & 50500020

pleas,help on such issues tha leads us to pay without having used such services .
while at the time of enquiries with service provider they just telling that it may be use by us,they have their own proof but how can we prove that we have not use it
it a serious crime,please,guide us to protect from such happening