Received same "source of funds" mail and a link to open an account at zendesk site. First I suspected it is some kind of spam or phishing but it is real. Quickly found this thread and immediately moved my funds away.
It is unbelieveable, am a long term regular user, I did KYC long time ago. I did not used their exchange very often but had coins in my account with this crappy exchange.
I was very stressed while waiting they are approving withdrawal request. It took them about 30 minutes to approve. Thanks to OP.