To cancel a booking then log into your account and select 'Show your own bookings'
From there you will be able to see a list of your upcoming bookings and you will be able to start the cancellation process
Depending on when the cancellation happens in relation to the start of the booking deductions might be made as the owner of the item may well have missed out on other bookings due to this booking being made, More details can be found here https://sportskitbuddy.com/uk/cancellation-policy