We, along with many others have had trouble with Stagecoach. On many occasions they have cut one of the early morning services. I have been in touch with the Public Transport Department in Cambridge regarding this issue, their reply is: -

If the bus does not turn up get a Taxi, ask for a receipt, and then send the receipt to: -

Stephanie Wade
Public Transport Department
Shire Hall
Cambridge.

She will get the cost of the taxi refunded to you from stagecoach. Do not forget to say which bus and at what time along with the date you were waiting for. Also, you should send a written complaint to: -