1000 loss by mistake,any way to recover it?

Negative balance will be recovered automatically with this ₹1000 credits & remaining amount (if any) can be withdrawn after reactivating the account by submitting KYC documents at the home branch.

RBI clearly states that - 

It should be ensured that the balance in the savings account does not turn into negative balance solely on account of levy of charges for non-maintenance of minimum balance.

If you want to fight it, then I would suggest escalating the issue to the bank through the proper channels and then the RBI Ombudsman.

https://www.rbi.org.in/commonman/English/Script...

Why have you left the account dormant? If you don't need it, ideally you should have closed it.

Approach the bank with kyc to reactivate it if you need the remaining funds