I can confirm the following:

I confirm ~10 BTC was sent just over 3 days ago, and OP (johnitrue) owns the sending address.
I confirm 2 support tickets at smartmixer.io, one >72 hours old, the other >48 hours old, have received only a generic automated reply.
I confirm smartmixer.io still doesn't provide a real Letter of Guarantee. All they give is a json file (apparently this can be used for their own internal verification).

The problem is: foul play can't be proven, because smartmixer.io doesn't provide a real Letter of Guarantee. They give something that's called that way, but it can't be independently verified. As a "classical" mixer, they have no reason not to provide a Letter of Guarantee, so the only reason I can think of for leaving this out, is to prevent an exit scam from getting confirmed. Just like what happened with BITMIXCOIN.IO scam confirmed: 16+ Bitcoin stolen. So the fact that this case can't be proven is actually on them. If they would have provided a Letter of Guarantee with a signed message, there would be no risk of any fake accusation every being credible. This is by their own design.
I confirm the receiving addresses in johnitrue json-file haven't received any funds. But because I can't verify the json, I can't conclusively say it's legit.
I have not found any reason to assume johnitrue is lying.

When trying to mix Bitcoin, smartmixer.io shows this:
Recently, they sent a customer his own coins (>30,000 USD). I don't believe they own even a fraction of 3910 BTC.

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johnitrue: can you create a Flag? If supported, it will create a very large warning on top of their Bitcointalk thread.