How to file case in consumer court

R/Sir , I am Amit Sharma and i purchased Sony xperia ZL on 20 march 2014 of Rs 26995 and it is covered in warranty upto 19 march 2016 by sangeetha mobiles. i had problem in my phone of mic and camera for which my mobile was given in Hyderabad dilsukh nagar outlet on 17 july 2015 and which was further sent to Bangalore service center and the it came to warangal center unrepaired on 28 august. i was again asked for 20 working day for repairing which i have proof of and after 20 working day my phone was un repaired and hence i have been offered a replacement with second hand sony xperia Z1 whose present costs is Rs 17990. I have already declined the offer for Sony xperia Z1 which was offered to me as a replacement asked for refund with compensation as they are not able to repair it and they are now sending me a swap model . (I have no idea which phone they are sending now ) . Also i was supposed to be delivered to me On 11th October but there is no sign of it till the date .. Sir, I have tortured many since 2 aug I tried to contact them regarding my phone status . Hence I want to file a case in consumer court so can u advice me regarding procedure and conpensation amount since it has been almost 3 monthhs