I'm trying to send a text to a new dog walker and it is saying that the phone number is already used?

In order to text a sitter you need to first create a booking request with the sitter. If you created a booking request and then received the message phone number already in use you will need to call Rover Support @ [Edit: Rover’s contact options have changed. Visit the Rover Help Center at https://support.rover.com/ to find the phone number, help articles, or chat with the team]