It seems they have already shut down the service voluntarily today, citing law enforcement measures towards them. See the announcement on
https://exch.cx.
I had tried to access their new main domain (exch.net) earlier and got an error.
exch.net is not resolved for me at the moment, even when the whois entry lists two Cloudflare nameservers.
exch.cx redirects to exch.pw which opens for me and doesn't show any signs of preliminary shutdown. They still announce their stop of accepting new orders on May 1
st there only.
eXch to stop accepting new orders starting May 1st (
announcement)
looks operational to me with the same announcement of stop of accepting new orders on May 1
st only.