If I have to cancel do I receive a refund?

Refunds for canceled bookings are determined by the sitter's cancellation policy, this article describes the different policy options https://support.rover.com/hc/en-us/ar...

Yes, you will need to cancel the booked stay to receive a refund. You can easily cancel the stay via the App and Web by clicking on "cancel stay" within the conversation itself. Once you submit that cancellation, then a refund will be processed.