Ola Cabs — did not come at end moment

Address:

Darjeeling, West Bengal

We were traveling with a patient to kolkata early morning from NJP via sharabdi express @4:30 am. We booked ola cab to go NJP railway station. But at the end moment it messages that sorry we are unable to send a car. In a believe that ola cab will come we didn't book any other car. And how is it possible for a person to get a caar early morning at 4:30 am. It is wrong they should have informed before since I booked the cab 2 days ago.