Anxiety About Sitter Possibly No Showing

Looking for a little feedback here as a first time Wag user. I booked a sitter earlier this week, they responded immediately to my open request and I booked them the next day. Our visit is scheduled this evening and I sent them a message this morning to confirm and go over a couple of things, but it's been 4 hours and no response.

I was already very anxious about the situation and counting on someone to show up from an app like this but now I'm starting to get really concerned. We have an important event to attend that cost a lot of money and will have to cancel if we don't have a sitter because our dog cannot be left alone, and I had a really hard time finding someone in the first place.

I don't want to try and book someone else and pull the rug out from her or have her just show up, but I don't want to be screwed over if they don't and I'm uncomfortable that they're not being responsive. But I don't want to be "that person" because I know people have jobs and lives and maybe she's just busy and unable to respond, but it's also a little strange to me that she wouldn't have spoken to me at all prior to the visit with being a new client. She does have good reviews (although one claimed a no show) and repeat customers and is a "wag pro".

Not sure what to do here and looking for some advice from those who are on the other side of the app.