I don't think its mintpal dumping, they gave me my 4k xc back.
How long ago did you get it back?
On the 16th, had to wait about an hour. I think the btc is gone though, its moved around quite a bit.
They did not get back mine 278.29047654 XC. It says
"Withdrawal Status
8ed8005d0712740eeddfe625d02fe7e80e135956ac163d1d473c36d264f4de76" .
So yes, they might be selling our coins, and that is normal in crypto world. We don't have chance to sue them for as low as 278XC or something like that, so they might figured out it is safe to give larger sums back, and keep a lots of low deposits, since owners would not bother for that. Like gox and all other fraudsters, they will be richer and we will get poorer...