Ola — OLA drivers asking extra money

In Coimbatore all the OLA drivers (Car, bike, auto ) first asking destination and price amount which is calculated by OLA. Then asking extra money Rs 30-Rs 50 based on the driver. If we ask the driver why we need to provide extra money.. they are scolding in bad words and asking us to cancell the trip. I have complaint through OLA but no response as usual. I was corner and booked another cab same question.. at this time I paid extra 50.. again and again on Saturday to Monday I booked more than 5 cabs all the drivers asked extra money. Please do something...