Its surprising that you know their forum profile link but you don't know about their ANN thread. Here it is, https://bitcointalk.org/index.php?topic=1935098.0.

Nah, I can't believe Chipmixer will scam you just for 0.1781BTC since you already stated that you mixed more than 10BTC from there. And I hope you have used correct web address since you are old user. Better option is raise your problem on their ANN thread instead of scam accusation. They have good reputation here and hope they will solved your issue.

Edit; seems OP made reply on ANN thread during make my post.