bad service from tata docomo

Location/place: Bangalore

Name of company/service: Mindstream infosolutions bangalore

Hello Sir/Ma’am

I am a post paid customer from jp nagar bangalore.
Since last two months i mam trying to move from postpaid to prepaid service.
The people of the docomo office here told me that u have to pay the whole amount,I did that.
After that they told submit the documents,,I did that.

After that the told call to the customer care,,I did that also,

Now still i am disturb its not done yet.

I am a software developer still i left my office 5 time within these two months just for the procedure for the same but still its postpaid only.

plz help me .

Hope u will take my request in a good way.

Thank You.

Qamar Islam