You can certainly cancel bus tickets that are booked using Niki. You can now do it from the app itself.
Go to My Orders under the Menu section and
tap on the Bus order listed.
Tap on Cancel Ticket button on the screen.
This will cancel the ticket. Just write to support to confirm the cancellation and process the refund.
Points to remember while cancelling your bus tickets from the app:
Cancellation charges will be applicable as per the travels’ policy and the balance will be processed as refund back to your account.
Any cashback earned as part of this bus ticket booking also will be reversed on cancellation of the ticket.
If the bus operator cancelled the bus, please do not cancel the bus ticket from the app. You might not get full refund for the cancellation because you cancelled the ticket. Drop an email to support about the bus cancellation from your operator, we will verify the cancellation and process a refund back to you.