Is there a phone number you can use to ask a sitter a question before you book??
If you click the Contact [Name}, it will send a message to the sitter. Usually, you'd want to schedule a meet & greet first to determine the match before you book and sometimes people exchange their phone numbers then. If for some reason a meet & greet isn't possible, you could explain and ask to exchange numbers when you contact the sitter.
Rover currently requires that you send an inquiry in order to initiate contact with a sitter. This will open a discussion with them but it doesn't obligate you to book a stay. It will require you to enter a start and end date for their services, but you can explain in the body of your message what your needs are, and those dates can later be changed as necessary. You can request to speak to them via phone, but many sitters prefer to use Rover's messaging system (especially initially) so that all the information is documented and accessible by Rover's staff.