They are having these issues for a long time now and they have disabled Zcash wallet on July 7 and they never gave an official explanation, something is going on with the site for sure,their customer support is not that good either,it is a good thing to avoid the site altogether until they get their things together.
until they announce it all of us still puzzled as the support really taking a lots of time before making some actions, I already stop using it right now
and move my coin to trex since they don't have any issue or serious issue yet, but like one of our mate said polo already got established business
I'm not sure if they greed to scam if they already have good source of earnings just hosting the trade.