Mobile no. is not deactivated since one month

Dear Sir/Madam,

I had an idea mobile no. 875004665, in my name and was used by one of my office person, who left the company and assured to hand over the SIM to me but did not gave the same. Last month i requested to deactivate the same.
Here is the request number for closure i received from the Idea,
Service Request No.C1-49263219100 would be actioned within22 hrs. by 27/08/2015 03:28:36 PM
Till date the same has not been processed and the person is using that SIM card. I followed the customer care and they are saying the they will not close the number.
The registered email for the same has also been changed without my consent.
My concern is that what action should be taken, both for the user and the service provider.

I look forward for your suggestion.

Thanks,

Karan Singh Bisht