Would you be able to give us any further information that this transaction has indeed taken place? Taking a look over their twitter account, it seems that they are still on it and are still responding to customer queries and such, just take a look in here: https://twitter.com/Changelly_team/status/943850502965678080

Try hitting up their customer support for more clarification about your concern. I've only used changelly once and it was about 4 months since I needed to have something done fast on conversion and haven't had any problems during that time. Honestly no one can help you in here except their own support team. It also looks like you're not the only one having problems as well.