Ola Cabs / Ani Technologies — extra charging

I travelled by cab no. Mh02cr8845 from cbd belapur to andheri (E), mumbai of ola cabs. Reference no. Is crn [protected]. At the time of booking the fare was shown as rs. 662/-. But at the end of the trip it became rs. 813/-. This difference is exhorbitant.
I asked the driver to contact their management and find out the reason but he refused to do so.
As i was in a hurry to go to airport to catch a flight to hyd, i could not proceed with argument and paid the amount to the driver. He was very headstrong and adamant.
While travelling from belapur, the driver advised that he will take cng gas on the way and for this purpose he diverted the vehicle towards vashi and took the gas and proceeded towards airoli. I asked him if there is any diversion in route, he said it doesnt matter. It took more than 15 minutes to take gas.
It is unfair to charge such an extra amount for no fault of mine. Hence i request you to please arrange for refund of the amount.

Regards,
Msn moorthy,
Agm (Retd), sbi