Perhaps filling out a add new coin memo will get their attention (https://docs.google.com/forms/d/e/1FAIpQLScsKp4EAZwBukhVrmvEw0Y8tL2FNqfu28bVEenSaiMdFoBiJQ/viewform).
Or their social media platforms:
https://twitter.com/changelly_team — https://www.facebook.com/changellyteam
https://plus.google.com/+ChangellyTeam
https://bitcointalk.org/index.php?topic=1435275.0
https://www.reddit.com/r/Changelly/
https://github.com/changelly
They may have been using some other exchange to do the matching like shapeshift did (or at least thats what I remember people saying shapeshift did in the past).