DoCoMo — Automatically number is ported to IDEA and using other person

Address:

Mahabubnagar, Andhra Pradesh

Hello Sir,

I am using [protected](AP Docomo) since from 5 years till 20th July @2012 after that i have been switched off my mobile becoz of work i went pune. now i am trying to switched on my mobile the message showing registration failed.
for that i called Docomo customer care they are say that number was ported to IDEA on 4th August 2012, but i did't did this one and that number is using some other person and he is saying he purchased that number by paying of 5000/-rs in the show room.

Q1) who did the number portability?
Q2) how to get my number back?
Q3) Whom we need to contact for this?

Number:[protected](Docomo)
Sim Number is[protected]

Thanks Advance
SANTHOSH ALOOR
[protected]