XDN-project is a separate project. XDN team is only dealing with cryptocurrencies development, not pools, not exchanges. We are working on XDN for almost 3 years and now also FCN.
Poloniex made a huge mess, it is very pity to have our reputation under attack because of Poloniex scam-alike actions. We are truly very glad to be delisted from this scam-alike exchange, they are acting like thieves stealing users coins. I hope users will have their coins back from Poloniex. There is NO XDN software or blockchain problems, the only thing they should do to send you your coins back is to update their wallets and daemons. There was NO XDN API change and the default block size limit now is 200kb so ALL transactions should be verified by the network.
You should ask poloniex to update their wallet and daemon - it is a 10-min action, they don't even need to resync. With the 200kb default block size they can transfer ALL of their user's coins in about 10 transfers.