I contacted a sitter in the Port Jefferson, NY area that was posted. Its been a month or more. Never heard a thing.
I'm sorry you haven't heard back from your potential sitter. That lack of response goes against Rover policies and recommendations. Like Daniela said, contact several sitters in your area, and give them about 48 hours to respond. If no answer, keep looking. I'm sure there are reputable sitters in your area who would love to help you out.
Rover does recommend that you contact at least three potential pet sitters, as not everyone checks their messages regularly or is always available. If you can, try contacting some more pet sitters in your area!
Find another sitter. If they don't have the time or dedication to check their profile for your inquiry, then you shouldn't wait around to entrust them with the care of your best buddy anyways. How can one expect them to diligently visit with response time like that? Most likely they created their account, found out about the 15% surcharge Rover takes, didn't like that and then never logged in again.
Definitely contact other sitters - if they haven't responded in a month, they aren't going to. Even though it's recommended, not all sitters respond to requests if they aren't available or interested. As a sitter, I see the same thing in reverse frequently. I'll receive a request, reply as soon as I get it (usually within minutes), and never hear anything back again. I usually wait a couple days, send one more follow up message ("Hi there, are you still in need of a sitter for these dates? I'd be happy to meet with you and Biscuit!") and then archive it.
When you're looking at other options, pay attention to the response rate listed on the sitter's profile. You're far more likely to get a timely reply from someone who has a 100% response rate and a reasonable response time. These are sitters who take themselves and their clients seriously, even if the stay isn't going to work out.
Good luck!