See wrote a letter to regional office of RBI and marking it to the head office you can get address from website and you can also contact them by using facility of contact us on RBI website.

1.  Both the dept., hardly entertain emails, more specifically for complaints, which have to be annexed with all relevant documentary proofs.

2.  Type out a detailed complaint letter, annex with all relevant documentary evidences and courier at the following address.

a)  Vigilance Dept., RBI, Worli, Mumbai

b)  EOW, Office of the Police Commissioner, Fort, Mumbai

You can do google search and obtain email I’d of RBI in Hyderabad and address where complaints are to be lodged 

OCI card holders can purchase residential and commercial properties in India. But they are not permitted to purchase agricultural land, including farmland or any kind of plantation property. A person, who had bought agricultural land / plantation property/farm house in India when he was an Indian citizen, can continue to hold that property without the approval of the Reserve Bank after becoming an OCI card holder.

As per your query registration of agricultural land is violation of Section 31 in The Foreign Exchange Regulation Act, 1973 and Section 6(3) in The Foreign Exchange Management Act, 1999.

You may file complaint before the land revenue officer or collector. Approach agricultural department for legal aide. Whenever file a complaint file any where user hard copies and not send it through email.

Sir,

      Do goggle and type email id of Hyderabad reserve bank of India. 

       You will get all the details there.

It's difficult to take redressal of your complaint through email I'd. You will a written complaint and send it by registered post. Action will be taken

No role of crime branch. Better complain to collector, he/she is revenue and agriculture land head.

Against whom you want to lodge the complaint and what are the details, please tell the same so that an appropriate advise can be rendered. 

Regards 

As per provisions of Foreign Exchange Management
Act, 1999 (FEMA] an Indian citizen or a foreign
citizen of Indian origin residing outside India, can
acquire any immovable property OTHER than
agricultural land. 

you can file complaint online visit FEMA site. 

Dear 

In your last query i have provided you Email ID of SP EOW( economic offence wing) 

Here are other details 

Dr. Mahender Kumar Rathod,
IPS, Superintendent of Police,
CID, EOW,
Office of the Additional Director
General of Police, CID, DGP.                           Office Complex, III Floor,
Lakdikapool, Hyderabad-500004
eow.khalid       @  yahoo.com

You can also send a written complaint on above address through registered post

Your complaint with RBI or crime branch police may not be effective or maintainable because this will come under state land revenue offences dealt by state land revenue department. 

You may approach them with a complaint by attaching substantial documentary evidences to support your complaint. 

You may have to give a complaint in writing and submit it to the concerned office either by registered post or in person. 

Dear Sir,

It is your duty to lodge complaints and further investigation about collecting emails etc lies upon the Investigation officers. Only prima facie case must be established by you.