Hit BTC seems to be the only exchange which trades CVC and this has proven to be a problem.
10 days ago transferred a 100k CVC to my HITBTC account. The site suggested that I enable 2FA for my protection and I did. When I logged back in, the site requested the 2FA code from Authenticator, which I provided and it would not accept.
I have not been able to access the site since. Not even using my backup code.
Multiple requests to HITBTC support, through reddit, through the support email address, and through contacting the HITBTC administrator have been ignored.
Hit BITC has had plenty of opportunity and time to respond and have not so I am left to conclude that I have been set up and that these tokens have been stolen .
After reading through other posts, it appears to me that many users feel that they have been scammed by this the HITBTC exchange.
My advice is to carefully consider what has happened to me before bringing your business to them.