I had a similar situation once. The client loved me, wanted to commit that night but didn't have her cheque book. Never contacted me again. I sent several emails ( i didn't take her phone number, lesson learned) finally I sent an email that said 'if I don't hear from you by XXX time I will assume you no longer need care and will offer the space to the next client' I got an email back saying her email wasn't working and she appologized and she wasn't comfortable with one part of my program so she opted out.

Point is.... move on! First one in with a deposit wins in my house and I make sure every one knows that. When I was looking for home daycares I didn't delay or wait, I got my confirmation in right away! If they're interested they will do the same.