they stole my big bundle

Very sad, man,
On the other side, your models are good enough to sell or no one will try to steal and sell them, next step should be some kind of 3D Designers guild to help protect our property, or look for another job.

Just send take down notice, usually helps, don't worry to much about it, happened to me many times, my sales is still ok.

Here are some take down notice examples (https://www.google.com/search?q=take+down+notice+example&tbm=isch&source=univ&sa=X&ved=2ahUKEwie0oukm4jiAhXRZFAKHW2EB3kQsAR6BAgJEAE&biw=1571&bih=1078)

Don't worry too much, it won't hurt your sales. People who need your models for project need to buy them, stolen models can't be used for commercial projects.

In this digital world it happens but It shouldn't affect your sales that much!

I can't help it. I can't avoid it

无奈