Post the LETTER OF GUARANTEE here as proof!
So you are trying to accuse cryptomixer.io? Why not try to post here the info's and as well as proof to support your claim. Many are using this mixer already and I don't think it will support your claim as they are a scam. And before anything else if you want to accuse them, go to the scam accusations board or if you are just experiencing a normal problem of delay, try contacting them again.