When someone submits the information they need as part of a request, they could also include the timeframe or deadline for when they need a response. It might also be helpful to indicate a percentage likelihood of receiving a response based on available matches.
This could be supported by categorizing each person when they log in and asking how they can help, offering different options. In this way, the platform could use that information to match requests with relevant people, increasing the chances that the right person is contacted to provide a response.