Hi Tammy,
I went through this almost same situtation last year. We had a pup from when she was five weeks to seven months old and we wanted to keep her more than anything. We adopted her out to people that I was alright with but not in love with for Kate. I started really missing her and having doubts about this placement, especially after my FI told me a little about her (she was a customer of his at a rent to own company), so I did a home visit check up and could not beleive how things were for my sweet sweet Kate. We did not pull her immediatly, but kept a very close eye and things only got worse! Moral of my story is, we all have intuition... If you are not feeling it, there is a reason you are not feeling it... Yes you love your foster and you want the best for them, so you will find it, no matter how long it takes you and how picky you are, you will find it... These people you described sound unreliable and unresponsible pet owners... good luck!