Aircel threatening me

A lot of cellular companies have been known to do this. However, I would suggest you wait till the Recover Team gets back to you, or you should call them again and follow it up. If they confirm that it is closed, then you can rest easy. If they dont respond after repeated attempts and any further e-mails or communications follow regarding unpaid balance, I suggest you file a case in Consumer Court against Aircel, with your various communications and the confirmation e-mail of payment as the primary evidence. 

file a consumer complaint in the district forum without waiting for their action.

Gotcha! Thank you Mr Suneel and Soumya. 

Before that issue a Registered Legal notice through Advocate, as issuing of such notice is desirable when you wish to file consumer complaint.  Wait upto 45 days after issuing the notice, and then if they still bring pressures, then file complaint.  See that every harassment with such chronological date is reflected in notice.  Later you can depend on the complaint and prepare a complaint yourself and attend the forum as party in person and maximum you may have to spend Rs.500/- as you will be demanding for costs and compensation of Rs.10,000/- it covers your expenses.  The procedure for filing complaint is not that much rigid as in Courts, and the proceedings are summary in nature, and it is not difficult for you to argue.  You can also authorise a representative for normal hearings and at the time of arguments you can appear in person.