Can you provide some more detail, please.  I've never used the Changenow service (fees are way to high,) but they've been around quite some time and I haven't heard of them being scammers before.  TrustPilot lists over 7k reviews with 4.8 stars average.  I'll refrain from discussing the reliability of TrustPilot reviews, that's another subject.

Are you sure you were dealing with the right site, and didn't get phished?