Number recycled Illegally

Location/place: Pune

Name of company/service: Airtel

I am an airtel prepaid subscriber with mobile number 9890318922. My number was illegally recycled by airtel telling me i did not use it for minimum 200 rs in 3 months. I have no idea about any such rule. Airtel claims it is TRAI rule.
Show me the rule.
Also if 200 Rs is the limit then i had picked up my phone twice while in international roaming and this was when i wasted 200 Rs. So i did use for 200 Rs right ???
Answer me airtel.
I WANT MY NUMBER BACK.