Uber India — charged extra for a ride

Address:

560068

Yesterday, i travelled from kempegowda international airport to devarachikkanahalli. The amount on my app showed 779.21 rupees. The driver asked me how much was it showing. I told the same amount. I paid 780 rupees. However, after the driver left from my place, the amount showed as rs.690. There's no way to contact the driver to ask the excess money back. Sadly, there's no customer care number to contact uber. I would like a refund of rs.90 that i've paid in excess.
I have contacted uber through twitter and their help postal through their app. But i have not received any response. If drivers cheat their customers this way, nobody would like to use this their services.