Uber India — I was overcharged by uber

I booked a trip for the airport on 19 mar 17 for the next day and was told to expect a bill of 915 - 1221rs.
The pickup point was rustam bagh road, old airport road, bangalore and the destination was kia (International airport)

On reaching the destination (Kia)... The charge was 6366rs.

I was told i had to pay the amount. Later on, after complaining they said that they had a gps issue and the bill was now 2047.90rs and the excess which i had paid will go to uber credit i. E rs 4318.
I want my cash refunded but they are not agreeing. After a terrible experience i am not keen on using uber.