Based on the op's accusation it will not be a wise decision to call a site as scammer. Because the OP had not provided enough evidence about the accusation and also the OP had just come to the site created the accusation and then left. If the lost amount was correct then OP could be more active.
But when you combine all this with other accusations like this
https://bitcointalk.org/index.php?topic=5477452.msg63892572#msg63892572 I would not lightly rule out the possibility that it is a scam exit.
I also saw that two reputable managers stated that they are no longer able to get in touch with their former Yomix contacts.