Mtnl trumph prepaid
Not registering do not disturb services on my phone

I had send sms on 1909 to start DND services so many time but not regisrering, replying that you have entered the wrong key, i tried so many times but all in vain. same time i got the service on my other phone no which is of vodafhone. please look into the matter an provide me the do not disturb services, i am very old custmer of mtnl trumph and i want to continue this subject to resolve my complient. my mobile no is 9869767338