I haven't even read this thread,
But from a compliance perspective
You would be flagged for money laundering immediately
Why would a genuine honest person who purchase 13BTC legally, who can provide proof of funds want to mix and hid the trail of BTC? Nobody legal would.
At best you are wanting to avoid tax, but a mixer would not be required for that.
You are a criminal, possibly a darknet vendor, scammer or hacker. A criminal who takes payment in BTC, the wallet address your BTC is held, is flagged as a dodgy address.
You cannot send it to a legitimate exchange as chain analysis will flag your wallet immediately and alert the compliance department.
My guess is the mixer you used also use chain analysis and saw your a dodgy wallet guy linked to crime.
The criminal had his money confiscated, and nothing you can do.
Live by the sword, die by the sword.
Can we get Mr 13BTC sourced from crime wallet address please? I would like to see