@Shauntae0 I too offer my space for longer term rentals and have had 2-3 months stays. On occasion my guest will leave for a few days to visit a neighboring are. 2 weeks is a significant amount of time to be gone though. My first assumption would be that they vacated the property, however if it was due to the issue with the dogs or something else, I am a bit surprised they wouldn't say anything further regarding their dissatisfaction.
I don't advise entering their area until it is confirmed if they are no longer occupying the space, but are there any personal items or indications that they are there? When most of my guest depart, they open the doors to their bedroom and bathroom and leave. If you are seeing their space open and no personal items left them again it would lead me to believe they vacated.
I think it is reasonable to send a polite message to check in. You don't even have to mention their absence. Just say something like "HI XXX, I just wanted to send a friendly check in to see how your stay is going thus far. Please reach out should you need anything. " Just be aware some guest are not big communicators and/or do not have app alerts on so they rarely respond. Ultimately, if they are not misusing the space or breaking rules you can let the reservation run its course.