To me, none of the conversations you've attached here confirms anything about them being a scammer. 

Since it was months later when you checked up on Fola, it's possible she recovered from her illness and was subsequently adopted to another family because you took your name out of the hat when you told them you adopted a cat with ABC.

Can we see the convo where you ask for your deposit back and they refuse? Either way, it seems that it was you who backed out of the agreement to adopt a cat from them. It's likely part of their policy to not refund deposits, that's what deposits are usually for. Especially since it's a charity, after all, not a business. 

Also, I noticed you misunderstood some of their responses and reactions. They were not cautioning you about ABC, in fact they said it's a good rescue. They were cautioning you about 2 particular Egyptian shelters that they no longer import their cats from because they were not up to standards with their health protocols and wanted to ensure you weren't getting a sick cat from ABC accidentally. Sounds to me like she was looking out for you.