I'm really sorry for your loss, bro.
But I'm also glad that this didn't happen to me cause that would make me become absolutely mad, I would fu***** be on their asses until they "found" those watches again or repay their market value + a 20% fee just for the stress burden. Seriously, no one simply loses something that valuable.
But like @StG pointed out, you had to have proper documentation to prove that they stole your watches so you could pursue your rights and maybe even sue their asses. I know it's a lot of hassle but, from my experience, when any company do any wrongdoings to you and just come with bullshit excuses like that, if you threaten to sue them with proper documentation/proof, they will solve the issue in record time.
Remember that no one can claim your rights but yourself.
I am not satisfied with the description that a company simply loses something of that value.
1. How did you send the watches there?
2. Do you have a tracking number?
3. Was the shipping insured?
4. Did you receive a receipt or job order conf. number from Lux?