Dear Sir,

- Do send him legal notice with all issues through registered post stating your grievances. 

- Have all the communication record available for future requirement for legal evidence. The complaint can be submitted to RERA tribunal 

- Builder is responsible to provide all the services agreed under BBA and RERA Tribunal is very strict on builder since inception of this act.

- No need to buy his tantrum.

Regards

Vivek Arya

Dear Sir,

- Below details for your kind reference please

   "Telangana State Real Estate Regulatory Authority"

     DTCP Building, Ground Floor,
     640, A.C.Guads, Masab Tank, Opp. PTI Building, 
     Hyderabad – 5000 004.

     Phone No.: [deleted], [deleted]

     TS RERA Office mail ID: [deleted]
     TS RERA Secretary mail ID: [deleted]

      http://rera.telangana.gov.in/

Regards

Vivek Arya

complain against builder before RERA seek orders to direct builder to obtain OC and deliver possession of flat to you 

2) in alternative complain to consumer forum seek orders to direct builder to obtain OC , deliver possession of flat , waive interest and pay compensation for delay in delivery of possession of flat 

You can approach Consumer court or rera as per your convenience. You will get the necessary reliefs in the said forums

Issue a legal notice to builder through an advocate and file a complaint in district consumer forum under defeincy of Service. 

I must say that entire process of possessing the flats by all owners has gone grossly out of law which may cause so many hindrances in getting legal help or any other remidial measure from civic authorities. 

First of all it is the responsibility of the builder to obtain completion certificate and occupancy certificate from the relevant competent authorities as per local law and to make it available to the allottees individually or to the association of the allottees. This is an essential requirements to make your possession legally valid.

Next you are liable to pay as per the  terms of allotment letter agreement which is generally align to stage wise time schedule of construction of the project.

Further if there is any structural defect or any other defect in workmanship quality or any other obligations of the builder as per the agreement, those things may be brought to the notice of the developer with in five years by any allottees from the date of handing over possession,  and it becomes the builder's liability to rectify all such defect within 30 days, in default an aggrieved allottee is entitled to receive appropriate compensation.

Communicate the builder stating all the requirements for needful action as per law. 

See you don't have to pay the interest on balance amount instead file a consumer complaint against the builder seeking compensation for dealy and mental agony.

Further the builder was wrong on part of not.giving possession with complete amenities on time.

The agreement with the builder has to be studied thoroughly in order to render you proper advice. Unless there is a clause for payment of interest, the builder is not legally entitled to it. 

The builder cannot demand the interest on the delayed payment. In fact it is not at all the delay in payment of balance amount since the builder has not completed the property and was not even in the position of registering the proeprty in a completed status.

You can refuse to pay the penal interest demanded by him and issue a legal notice to him instructing him to register the property by receiving the balance of amount due to him other than the interest amount demanded by him.

After that you can approach consumer court against him for deficiency in service and for relief  as well as compensation for mental agony