You need to file suit to set aside registered release deed as there is no such survey number as mentioned in release deed 

2) enclose copy of reply received from BBMP 

Dear Sir,

You cannot write to Sub-Registrar to cancel release deed. It has to be cancelled by the person who executed release deed by visiting Sub-Registrar office personally. Otherwise you have to file a suit for cancellation of such release deed by making the executor as Defendant in the suit.

See if the release deed is wrognly registered with cheating and fraud you have to file suit before civil court the sub registrar doesn't have power to cancel the deed.

1. Once a Release Deed is registered, it can be revoked /rescinded /canceled only by a Civil Court order, who would give directions to the area Sub-Registrar and also for filing FIR for the Fraud, Forgery & Cheating against the person who produced the Fake Khata Extract.

You can go before civil court for cancellation of the same on fraudulent deed

When no such kahta no, land ever exits, nothing has released. Or more particularly, portion of land is release through deed from no land.

No need of cancellation deed. Map attach to release deed ?

Cancellation of a registered document can be done at the sub-registrar's office if both parties consent to such cancellation. If either party to the original deed refuse to come forth for cancellation, then the party seeking cancellation must seek out his remedy through a competent civil court only.

writing a letter to the sub-registrar for cancellation will not help.

1. You have to file suit to set aside the registration of release deed. 

2. The ground should be that khata no. Mentioned in release deed doesn't exist aa per records of BBMP 

Registered release deed has nothing to do with the khata.

A registered release deed can be executed by the cosharer in favor of another shareholder only.

The khata may be fake but where is the khata coming into picture to the registered document.

The sub registrar cannot cancel the release deed, you can approach only court of law seeking to cancel the registered release deed provided you are a party to the said transaction.

If release deed executed and registered a legally valid,  it can not cancel it now. through court only you can cancel, enclose RTI certified copy of BBMP.