Mts — False bills : asking me to pay for the service i never used.

Address:

New Delhi, Delhi

I bought mts dongle in Jan and paid all the bills till i was using it. i called mts on 16th march from [protected] number. i requested for deactivating it as i was moving to mumbai. next day i received message that your request 1410675 has been processed. Now MTS executive is saying that someone else called on 19th march and reactivated it. My question is why and how you can activate my number from a call from unregistered number. MTS generated the bill for next 2 months and asking me to pay. Also, i never get any notification that your internet device has been activated again. I never used MTS internet after 16th of march. I have already paid amount till march. Please guide me what should i do ? Vivek