I tried to contact them again , but no answer
the website is : Coinmama.com
Sorry to hear about your trouble with the payment! Without knowing the specifics, it sounds like the the charge you see is only an authorization hold.
How can you say "there is no specifics" when OP said you're not responding to his ticket?
Hey Frodoe after reading all the comments all I can say you'll be lucky if you get your funds back, I had never heard of this exchange before so decided to a quick search, and it's pertinent to note there're many positive comments I'm going to highlight the ones that match fredo case, in this link http://bittrust.org/coinmama
if you see from the top there's a similar story, and that user I suppose didn't get his funds. As I see there's a coin mama representative here I'm sure we'll get some answers.
For all newbies whenever you buy online do a quick google search, read about them here, avoid exchanges you can buy here using escrow just a quick search here will list all escrows, and reputed sellers.
Fredo do let us know what happens if you're not refunded or credited then simply open a scam accusations thread.