If using Namma Yatri for airport and going non-toll road, make sure driver ends ride before payment

Happened with me twice. Namma Yatri's initial price estimate for airport is through toll road (toll tax included). Driver will take non-toll road and say the initial estimate was for non toll only and will charge toll separately for toll road. If you choose to take non-toll road he will share the scanner just after entering airport area and ask you to pay the initial amount. They will end the ride only after leaving and the final trip cost will be lower then the initial estimate (diff was exactly the cost of toll). Second time this happened, I refused to pay earlier and asked him to end ride first. First he was saying it will take more time in airport drop zone so I should pay then only. Later at the drop zone he said some issue with app and he is not able to end trip.