If you want, you can send me some of the transaction data (a single deposit adress with a signed message from the input made to that deposit address). Note that i can't promise anything though. (Since their LoG isn't a LoG, i think it will be hard to verify with 100% certainty, nonetheless..)
I suspect that "smartmixer" - just might say - * the signature is not mine (but no one can check), I didnt have you, I dont know who you are * - given the size of the amount sent.
Such a statement would, depending on the data you have, be sufficient in proving they perhaps did steal the funds.
EDIT:
I can verify that OP has had control over 10+
BTC. Whether they were actually send to Smartmixer,, ...i will try to verify that in a bit.
Edit2: as of right now i cant verify (with certainty) whether the funds were actually send to Smartmixer. I still feel like this warrants a response from them.