It appears that the site that you went to is fake. The real site is
https://chipmixer.com/. You have been ripped off by a scammer, putting up a phishing site.
It's not a phishing site, i've used the same onion address earlier and my chips came through immediately after a confirmation.
They doesnt answers emails and i think their user need to be banned from this forum if they do not answer this topic.
They won't be banned if they don't reply in this thread but if your issue doesn't get fixed it would hurt chipmixer's reputation. I'm confident it'll eventually get resolved given their big reputation.