I agree with pretty much everything everyone else has already said.
I'm sorry someone treated you like this. I'm not sure if this was a family member or just a friend....and not knowing the person makes forming a judgment about them sorta hard....but I'd guess they are a little embarrassed and don't know how to justify their breach of trust other than to just blow it off.

I don't know...just drawing straws here.
If it were me I'd do everything in my power to make it right. I couldn't live with myself if I didn't.
I think people make promises to quickly these days. They don't feel like it matters if they keep them or not. My Mom always told us not to make promises we couldn't keep. And I don't recall her ever breaking a promise to any of us girls.
I hope this resolves itself for you soon, Beth. I hate it that you tried to do something kind for someone and they brushed you off.