I am having the same problem mate, I sent an email in and they said they paid me when in fact they didn't as like you they were on the wrong chain at the time when they sent them. I sent them another support ticket with the current block explorer thanks to CryptoDatabase but have not heard a word from them since which is now over 1 week. I'm now thinking that I'll never get my honey from them, lucky for me it was a small amount but for you 400 is a lot to lose. I'm not sure what to suggest.