Now site is back up and withdrawing works like a charm, so clearly the problems at coinmarket are not scamm but just pure amateurism in how to run a business.
I don't know if it's a scam, but it definitely doesn't work like a charm. I got 2M Reddcoins there which I tried to withdraw, got a confirmation etc, but then they said they were on a forked chain so had to process withdrawals manually. Till now I'm still waiting for a newer comment on that.
PS. coinmarket admins, if you're reading this, same username, 2M RDD stuck, please do something or at least let me know if I should just forget them.