I never saw any LoGs when I did the procedure. It only gave me an order id and its passphrase. Once I made the transaction I saved both and then closed the site. It took a 2-3 days for the transaction to be confirmed, so once it did, I went back in mycryptomixer.com to see how it's going.

When did it give you this LoG? I signed a message from the sender address and I can also PM the order id + passphrase to @MyCryptoMixer. I wonder how better proof can one provide.