Don't know what happened or why but if I were you I'd start moving them to Cryptopia before everyone else tries to, or you might get caught in the traffic jam! I am using Cryptopia and though it's not as user-friendly as some exchanges, its reliable, support is good and quick and there is a good, helpful community. (I believe it may be owned and operated by Kim Dotcom). You could do worse, take Bittrex for example, constantly causing problems for users and delisting coins for no good reason.