My driver ended up getting a $13+ tip when it was supposed to be $6.60 based on 20%. There were added fees which shouldn't be in the calculation, but even that didn't add up. There is no way to change tip after the ride except to add to it. No customer email or phone. This tip some how doubled. Jan 25 2022 : Sent email as per you instructions. Now Feb 19 2022 and haven't heard back and didn't expect to.