Poor mileage and poor service by company

I bought Beat Deisel (LT) from Chevrolet dealer AAKRITI WORLD JALANDHAR on Feb 17th, 2014. At the time of visit, I asked the representative that this model should have Steering Audio Control. I will buy this car only If you will add this feature and it should give a mileage of 25kmpl. Sales representative and Manager of AAKRITI WORLD SHOWROOM committed that they will certainly provide these feature within 15days or before 1000Kms for me. So, I bought the car in white color. Now my car has run 13000kms, I asked them several times for Steering Audio Control System. But every time the sales representative gave me a false commitment that it will be done within 2 - 3 days, etc. I am sharing my experience with this car. I drove it about 13000kms in 7 months and my experience has been very bad. The mileage is only 16 -17 without AC. I always filled the diesel tank to its full capacity of 37 liters and drove it until it gets finished. It would be over by 620 OR 630 kms. I have filed repeated complaints of poor mileage with the dealer at the time of first and second service.  Complaint Suggestions 1. There is not rear light for rear seats in Beat Diesel LT. 2. There is no light in the trunk  3. Seats are not comfortable for long drives(foams are very thick and of bad quality)  4. No indication of temperature  5. No mileage average indicator and no Bluetooth.  6.I can't see the speedometer clearly in the sunshine.(Speedometer should have a plastic cover for shadow)  7. No Central locking with remote and security system in this variant (top end version)  8. No electrically operated mirrors  9. AC is not effective  10. No rear parking sensor  11. Front and rear side pillar are very wide, I cannot see right and left easily  12. No seat pockets, no glass holder for rear seats  13. It's only a 3 cylinder 936cc engine. It should give a mileage of 25kmpl+ but I am getting only 16kms. I also drove Tata Manza, its 1300cc, but it's giving the mileage of 18kmpl with AC. Note Beat diesel LT is totally a useless and featureless car for me and also it's not giving me 25kms as committed by the salesman at the time of purchase. As it costs 6,10,000, it's very expensive if we compare its features with other car companies.